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193                                                                                                  General Session

Head-to-head comparison of 68Ga-PSMA-11 PET/CT and mpMRI in the detection, intra-prostatic
localization, and local extension of primary prostate cancer: A single-center imaging study with
histopathology gold-standard.

Ida Sonni, Ely Felker, Andrew Thomas Lenis, Anthony E Sisk, Shadfar Bahri, Martin S. Auerbach, Wesley R Armstrong,
Voraparee Suvannarerg, Teeravut Tubtawee, Tristan Grogan, David Elashoff, Johannes Czernin, Steven Raman,
Robert Evan Reiter, Jeremie Calais; UCLA, Los Angeles, CA; UCLA School of Medicine, Los Angeles, CA; University of
California Los Angeles Department of Pathology, Los Angeles, CA; Department of Molecular and Medical Pharmacology,
University of California, Los Angeles, CA; Ahmanson Translational Theranostics Division, University of California, Los
Angeles, CA; University of California Los Angeles, Los Angeles, CA; University of California, Los Angeles, CA; David Geffen
School of Medicine, University of California, Los Angeles, Los Angeles, CA; Institute of Urologic Oncology, University of
California, Los Angeles, CA

Background: The local staging of prostate cancer relies on systematic or targeted biopsies and
multiparametric magnetic resonance imaging (mpMRI). The role of prostate-specific membrane
antigen (PSMA)-targeted PET in the evaluation of intraprostatic cancer foci and T-staging as-
sessment is not well defined. The goal of this analysis was to compare the diagnostic performance
of PSMA PET/CT, mpMRI and the combination of the two (PSMA PET/CT+mpMRI) in the detection,
intra-prostatic localization and local extension of primary prostate cancer with histopathology as
the gold standard.Methods: Patients with intermediate- or high-risk prostate cancer underwent a
PSMA PET/CT scan and mpMRI prior to intended radical prostatectomy. Each imaging modality
was interpreted by 3 blinded independent readers. A majority rule was applied (2:1). A standardized
approach was used to assess presence, location and size of prostate cancer foci within the
prostate. The analysis was conducted on a lesion- and segment-level. Whole mount pathology was
interpreted by a Genito-Urinary pathologist using the same standardized method described above.
Accuracy in determining the location, extra-capsular extension (ECE) and seminal vesicle invasion
(SVI) of prostate cancer foci were assessed using receiver operating characteristic (ROC) analysis.
A “raw-stringent” and “neighboring” approach were used to define imaging/pathology correlation
for the detection of individual prostate cancer foci. Results: The final analysis included 74 patients.
Detection rate was 75%, 79% and 82% using the “raw-stringent” approach, 86%, 83% and 87%
using the “neighboring” approach for PSMA PET/CT, mpMRI and PSMA PET/CT+mpMRI, respec-
tively. Differences in detection rates between PSMA PET/CT, mpMRI and PSMA PET/CT+mpMRI
were not statistically significant. The two imaging modalities performed similarly (AUC = 0.70 vs
0.73, p = 0.09; AUC = 0.77 for the two together) in localizing prostate cancer. DAUC between PSMA
PET/CT+mpMRI and the two imaging modalities alone was statistically significant (p , 0.001), but
not between PSMA PET/CT and mpMRI (p = 0.093). mpMRI performed better than PSMA PET/CT in
the T-staging assessment: ECE (AUC = 0.79 vs 0.59, p = 0.002) and SVI (AUC = 0.84 vs 0.63, p =
0.001). Conclusions: PSMA PET/CT and mpMRI have similar diagnostic accuracy in the detection
and intra-prostatic localization of prostate cancer foci while mpMRI performs better in the
assessment of ECE and SVI. The combination of the two imaging modalities improves performance
of the two modalities alone, but this does not reach statistically significant levels on a lesion-level
and might not justify changes in the current practices for local staging of prostate cancer.
Research Sponsor: None.

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
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194                                                                                        Oral Abstract Session

Dose-intensified versus conventional dose-salvage radiotherapy for biochemically recurrent
prostate cancer after prostatectomy: Six-year outcomes of the SAKK 09/10 randomized phase
III trial.

Pirus Ghadjar, Stefanie Hayoz, Juerg Bernhard, Daniel Rudolf Zwahlen, Tobias Hoelscher, Philipp Gut, Bülent Polat,
Guido Hildebrandt, Arndt-Christian Mueller, Ludwig Plasswilm, Alexandros Papachristofilou, Corinne Schaer, Marcin Sumila,
Kathrin Zaugg, Matthias Guckenberger, Piet Ost, Christiane Reuter, Davide Giovanni Bosetti, Kaouthar Khanfir,
Daniel M. Aebersold; Charité Universitätsmedizin Berlin, Berlin, Germany; Swiss Group for Clinical Cancer Research, Bern,
Switzerland; International Breast Cancer Study Group, Bern, Switzerland; Kantonsspital Graubuenden, Chur, Switzerland;
University Hospital Dresden, Dresden, Germany; Hirslanden Hospital Group, Zürich, Switzerland; Radiation Oncology,
University Hospital Würzburg, Wurzburg, Germany; University Hospital Rostock, Rostock, Germany; Department of Radiation
Oncology, University Hospital Tübingen, Tübingen, Germany; Department of Radiation-Oncology, Kantonsspital St. Gallen, St.
Gallen, Switzerland; Department of Radiotherapy and Radiation Oncology, University Hospital Basel, Basel, Switzerland;
SAKK, Bern, Switzerland; University Hospital Zurich, Zurich, Switzerland; Ghent University Hospital, Ghent, Belgium;
Kantonsspital Münsterlingen, Münsterlingen, Switzerland; Istituto Oncologico della Svizzera Italiana, Bellinzona, Switzer-
land, Bellinzona, Switzerland; Hôpital Valais, Sion, Switzerland; Department of Radiation Oncology, Inselspital, Bern
University Hospital, University of Bern, Bern, Switzerland

Background: Salvage radiotherapy (RT) is often utilized in case of biochemical progression after
radical prostatectomy (RP). Here we report the outcomes of the European SAKK 09/10 randomized
phase 3 trial with the aim to compare effectiveness and tolerability of conventional vs. dose-
intensified salvage RT. Methods: SAKK 09/10 is an open-label, multicenter, randomized phase 3
trial performed in 24 centers in Switzerland, Germany and Belgium. Men with biochemical
progression (two consecutive rises with the final PSA . 0.1 ng/mL or three consecutive rises)
after RP with a PSA nadir of # 0.4 ng/mL, with a PSA # 2 ng/mL at randomization and without
clinical evidence of macroscopic disease were recruited. Patients were randomly assigned to either
conventional dose RT (64 Gy in 32 fractions) or dose-intensified RT (70 Gy in 35 fractions) directed
to the prostate bed. Three-dimensional conformal RTor intensity-modulated RT/rotational tech-
niques were used. The primary endpoint was freedom from biochemical progression (PSA $ 0.4
ng/mL and rising). Secondary endpoints included clinical progression-free survival, time to hor-
monal treatment, overall survival, acute and late toxicity (according to the NCI CTCAE v4.0) and
quality of life (according to the EORTC QLQ-C30 and PR25). The trial was registered under
NCT01272050 in clinicaltrials.gov. Results: Between 02/2011 and 04/2014, 350 patients were
randomly assigned to 64 Gy (n = 175) or 70 Gy (n = 175), of whom 344 aged between 48 to 75 years
were assessable for the intention-to-treat population. The median PSA at randomization was 0.3
ng/mL (range, 0.03-1.61 ng/mL). At the time of data cutoff (July 3, 2020), the median follow-up was
6.2 years (IQR 5.5-7.2) and a total of 138 biochemical progression events occurred. The estimated
freedom from biochemical progression rate at 6 years was 62.3% (95% CI 54.2-69.4%) and 61.3%
(95% CI 53.4-68.3%) for the 64 Gy and the 70 Gy arm, respectively, and the hazard ratio adjusted
by stratification factors was 1.14 (95% CI 0.82-1.60; log-rank p = 0.44). No significant difference
was found for clinical progression-free survival, time to hormonal treatment and overall survival
between the two arms, respectively. Late grade 2 and 3 genitourinary toxicity was observed in 35
(21.2%) and 13 (7.9%) patients treated with 64 Gy, and in 46 (26.3%) and 7 (4%) patients with
70 Gy (p = 0.81). Lategrade 2 and 3 gastrointestinal toxicity was observed in 12 (7.3%) and 7 (4.2%)
patients with 64 Gy, and in 35 (20%) and 4 (2.3%) patients with 70 Gy(p = 0.009). Quality of life
data will be presented. Conclusions: Dose-intensified salvage RT to the prostate bed was not
superior to conventional dose RT. However, dose-intensified salvage RT was associated with
higher frequencies of late grade $ 2 gastrointestinal toxicity. Clinical trial information:
NCT01272050. Research Sponsor: Hedy and Werner Berger-Janser Foundation, Swiss cancer
research foundation, Radio-Onkologie Berner Oberland AG and Swiss State Secretariat for Edu-
cation, Research and Innovation (SERI).

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
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195                                                                                        Oral Abstract Session

Association of the clinical cell-cycle risk score with metastasis after radiation therapy and
identification of men with prostate cancer who can forgo combined androgen deprivation
therapy.

Jonathan David Tward, Constantine Mantz, Neal D. Shore, Paul Nguyen, Isla Garraway, Carl A Olsson, Steve Pai-hsun Lee,
Arthur Hung, R Jonathan Henderson, Stanley L. Liauw, David Raben, Michael D. Fabrizio, Daniel R. Saltzstein, Paul Yonover,
Hiram Alberto Gay, Daniel Joseph Albertson, Tatjana Antic, Lauren Lenz, Steven Stone, Todd Cohen; Huntsman Cancer
Institute, University of Utah, Salt Lake City, UT; 21st Century Oncology, Fory Myers, FL; Carolina Urologic Research Center,
Myrtle Beach, SC; Dana-Farber Cancer Institute, Boston, MA; Veterans Affairs Medical Center Los Angeles, Los Angeles, CA;
Integrated Medical Professionals, PLLC, Columbia University Medical Center, North Hills, NY; Long Beach VA, Long Beach, CA;
Oregon Health & Science University Department of Radiation Oncology, Portland, OR; Regional Urology, LLC, Shreveport, LA;
University of Chicago Pritzker School of Medicine, Chicago, IL; University of Colorado, Aurora, CO; Urology of Virginia,
Virginia Beach, VA; Urology San Antonio, San Antonio, TX; UroPartners, Chicago, IL; Washington University School of
Medicine, Department of Radiation Oncology, St. Louis, MO; University of Utah Huntsman Cancer Institute, Salt Lake City, UT;
University of Chicago, Chicago, IL; Myriad Genetics, Inc., Salt Lake City, UT

Background: This study evaluated the ability of the combined clinical cell-cycle risk score (CCR) to
prognosticate the risk of prostate cancer metastasis in men receiving dose-escalated radiation
therapy (RT) with or without androgen deprivation therapy (ADT). Methods: The CCR score is a
validated model that combines the cell cycle progression score (CCP) with the UCSF Cancer of the
Prostate Risk Assessment score (CAPRA). The CCR score and a CCR-based multimodality threshold
score (2.112) were evaluated in a retrospective, multi-institutional cohort of men with National
Comprehensive Cancer Center (NCCN) intermediate- or high-risk localized disease (N = 741) who
received single (RT) or multimodality therapy (ADT with RT). Effects of prognostic variables were
analyzed using Kaplan-Meier and Cox regression methods. Results: Median follow-up was 5.9
years. CCR predicted metastasis [hazard ratio (HR) 2.21, 95% Confidence Interval (CI) 1.70-2.87,
p , 0.001]. The CCR score was a better prognosticator of metastasis (C-index 0.78) than either
NCCN-risk group (C-index 0.70), CAPRA score (C-index 0.71), or CCP score (C-index 0.69) alone. In
bivariate analyses, the CCR score remained highly prognostic for metastasis when comparing any
ADT vs none (HR 2.19, 95% CI 1.62 to 2.97, p , 0.001), ADT duration as a continuous variable (HR
2.05, 95% CI 1.54-2.72, p , 0.001), or ADT use given as less than or at the recommended duration
for each NCCN risk group (HR 2.22, 95% CI 1.71-2.88, p , 0.001). Men with CCR scores either below
or above the threshold (2.112) had a 10-year risk of metastasis of 4.2% and 25.3%, respectively. For
men below the threshold receiving RT alone versus RT+ADT, the 10-year risk of metastasis was
4.2% and 3.9%, respectively. Conclusions: CCR is a highly precise and accurate predictor of
metastasis in men undergoing dose-escalated RT, with or without ADT. CCR adds clinically
actionable information relative to guideline recommended therapies that are based on NCCN
risk groups or CAPRA alone. Men with scores below the multimodality threshold may not signif-
icantly reduce their 10-year risk of metastasis with the addition of ADT. Research Sponsor: Myriad
Genetics, Inc.

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
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196                                                                                                    Poster Session

PSA velocity to predict clinical progression in African American and non-Hispanic White patients
with low-risk prostate cancer undergoing active surveillance.

Juan Javier-Desloges, Tyler Nelson, Patrick Travis Courtney, Rishi Deka, Vinit Nalawade, Loren K. Mell, James Don Murphy,
J Kellogg Parsons, Brent S. Rose; UC-San Diego Health, San Diego, CA; University of California San Diego, School of Medicine,
Department of Radiation Medicine and Applied Sciences, La Jolla, CA; UC San Diego Health System, La Jolla, CA; University of
California, San Diego, La Jolla, CA; University of California San Diego Moores Cancer Center, La Jolla, CA; University of
California, San Diego Department of Radiation Medicine and Applied Sciences, La Jolla, CA; UCSD Moores Cancer Center, La
Jolla, CA

Background: The utility of prostate-specific antigen velocity (PSAV) to predict clinical progression
in patients with localized prostate cancer (PC) on active surveillance remains unclear, and in
African American (AA) patients on active surveillance remains undefined. Methods: We
performed a cohort analysis using the national US Veterans Affairs Informatics and Computing
Infrastructure (VINCI). We identified 5296 patients diagnosed with localized prostate cancer (PC)
from 2001 to 2015 managed with active surveillance. Follow-up extended through March 31, 2020.
We defined low-risk PC as ISUP grade group 1 (GG1) clinical tumor stage # 2A, and PSA level # 10
ng/dl; and active surveillance as no definitive treatment within the first year after diagnosis with at
least one additional staging biopsy after diagnostic biopsy. The primary outcome was grade
progression on repeat biopsy/prostatectomy defined as GG2 or GG3. The secondary outcome was
incident metastases. Cumulative incidence functions and multivariable Cox proportional hazards
models were used to test associations between PSAV and outcomes. Results: The final cohort
included 3919 Non-Hispanic White patients (NHW) (74%) and 1377 AA (26%) patients. GG2
progression on repeat biopsy occurred in 2062 (38.9%) patients, with a cumulative incidence
(CI) of 43.2 % and GG3 progression occurred in 728 (13.7%) patients, with a CI of 18% at seven
years. Fifty-four (0.8%) patients developed metastases, with a CI of 1.4% at ten years. In
unadjusted analyses, compared to NHW patients, AA patients were significantly more likely to
progress to GG2 (52.8% vs 39.8%, p,0.001), and GG3 (22.2% vs 16.8%, p=0.01). On MV analysis,
PSAV was a significant predictor of GG2 (HR 1.32 [1.26-1.39]), GG3 (1.5 [1.40-1.62]), and metastases
(1.38 [1.10-1.74]). A significant interaction term between race and PSAV indicated the need for
different PSAV thresholds for AA and NHW men. Based on maximally selected rank statistics,
optimal thresholds for separating outcomes were different in AA vs NHW men. (0.44 vs. 1.18).
Conclusions: In this analysis of PSAV in low-risk prostate cancer patients on AS—to our knowledge,
the largest to date for AA patients—we observed that PSAV is a robust predictor of upgrading on
restaging biopsy as well as metastasis. Compared to NHW patients, AA patients were more likely to
progress at lower values of PSAV and therefore merit close follow-up on active surveillance
protocols. Research Sponsor: Department of Defense, grant number W81XWH-17-PCRP-PRA (RD
and BSR).

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
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197                                                                                                       Poster Session

An FDA pooled analysis: Characteristics and outcomes of patients with nonmetastatic
castration-resistant prostate cancer, based on prior history of prostatectomy and/or
radiation therapy.

Jaleh Fallah, Lijun Zhang, Chana Weinstock, Daniel L. Suzman, Shenghui Tang, Kirsten B. Goldberg, Paul Gustav Kluetz,
Julia A. Beaver, Richard Pazdur, Amna Ibrahim, Laleh Amiri-Kordestani; U.S. Food and Drug Administration, Silver Spring, MD

Background: Patients (pts) enrolled in trials of androgen receptor inhibitors (ARI) in the non-
metastatic castration resistant prostate cancer (nmCRPC) setting may or may not have received
definitive treatment with prostatectomy and/or radiation therapy (Surg/RT). We investigated the
characteristics and outcomes of pts with nmCRPC based on prior history of Surg/RT. Methods:
Data were pooled from all trials of ARI in nmCRPC submitted to the FDA as of October 2020. Pts
baseline characteristics were summarized by prior history of Surg/RT. The Kaplan-Meier method
was used to estimate median metastatic-free survival (MFS) and overall survival (OS) of each
treatment arm by prior history of Surg/RT status. Hazard Ratios (HR) with corresponding 95%
confidence intervals (CI) were estimated using a Cox proportional hazards model stratified by trial
and adjusted for baseline characteristics. Results: Three trials met the inclusion criteria. Of 4117
pts enrolled, 2251 (55%) had prior surg/RT. The median age at the time of enrollment was 72 and
76 years in pts with and without prior Surg/RT, respectively. The median time from initial diagnosis
of prostate cancer to enrollment on the trials of ARI was 9.1 and 5.7 years in pts with and without
prior Surg/RT, respectively. PSA doubling time and number of prior hormonal therapies were
similar between the two groups with and without prior Surg/RT. History of prior Surg/RT varied
by geographic region: 76% (N = 611/807) in North America, 50% (N = 1110/2229) in Europe, 39%
(N = 220/570) in Asia/Pacific, 52% (135/262) in South America, and 73% (171/233) in Australia/
New Zealand. ECOG performance status (PS) at the time of enrollment was 0 and 1 in 80% and
20% of the pts with prior Surg/RT, respectively. In pts without prior Surg/RT, ECOG PS was 0 in
65% and 1 in 35% of pts. Gleason score was $8 in 36% and 47% of pts with and without prior Surg/
RT, respectively. MFS and OS results in pts with and without prior Surg/RT are in the table.
Conclusions: In this retrospective analysis, MFS and OS was improved in pts who received ARIs
compared to placebo, regardless of prior history of Surg/RT. Any relative differences based on
prior history of Surg/RT can only be considered hypothesis generating. Research Sponsor: None.
Use of Surg/RT for localized prostate cancer varied by geographic region which may reflect
the differences in standard of care or access to healthcare.
                                                   Median time (mo)
                     Endpoint    Event, N (%)    in ARI vs placebo arm     HR (95% CI)
Prior Surg/RT: Yes     MFS          690 (31)            40 vs 15          0.26 (0.22, 0.31)
                        OS         624 (28)             74 vs 61          0.73 (0.61, 0.87)
Prior Surg/RT: No      MFS         480 (26)             41 vs 26          0.41 (0.34, 0.50)
                        OS         524 (28)             67 vs 55          0.68 (0.57, 0.82)

          © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
PROSTATE CANCER - LOCALIZED

198                                                                                                       Poster Session

The association between sexual orientation and screening of prevalent gender-specific cancers.

Michael Joseph Herriges, Ruben Pinkhasov, Keren Lehavot, Oleg Shapiro, Joseph M Jacob, Thomas Sanford, Nick Liu,
Gennady Bratslavsky, Hanan Goldberg; SUNY Upstate Medical University, Syracuse, NY; VA Puget Sound Health Care System,
Seattle, WA; Department of Urology, Upstate Medical University, Syracuse, NY; SUNY Upstate University Hospital, Syracuse,
NY; Department of Urology, SUNY Upstate, Syracuse, NY

Background: Data on heterogeneity in cancer screening and diagnosis rates among sexual
minorities (SMs) is lacking. Recent studies have shown SMs are more likely to engage in risky
health behavior and have decreased healthcare utilization. However, few studies have examined
how sexual orientation impacts cancer screening and prevalence. We therefore investigated
whether sexual orientation affects prevalent gender-specific cancer including prostate (PCa),
breast (BC), and cervical cancer (CC). Methods: This was a cross-sectional survey-based US study,
including men and women aged 18+ from the Health Information National Trends Survey (HINTS)
database (part of the National Cancer Institute’s division of cancer control and population
sciences) between 2017-2019. The primary endpoint was individual-reported PCa, BC, and CC
screening and prevalence rates among heterosexuals and homosexuals/bisexuals. Multivariable
logistic regression analyses assessed association of various covariates with undergoing screening
and diagnosis of these cancers. Results: Overall, 4,441 and 6,333 heterosexual men and women,
respectively, were compared to 225 and 213 homosexual/bisexual men and women, respectively.
Homosexuals/bisexuals were younger and less likely to be screened for PCa (34.7% vs 41.3%,
p=0.013), BC (54.5% vs 80.7%, p=,0.001), and CC (88.3% vs 95.4%, p=,0.001). While rates of
PCa and BC diagnosis were similar, more than twice as many homosexual/bisexual women were
diagnosed with CC (4.2% vs 1.9%, p=0.023). Multivariable logistic regression models (Table)
showed homosexuals/bisexuals were less likely to be screened for cancer with ORs of 0.61 (95% CI
0.39-0.95) for PCa, 0.52 (95% CI 0.30-0.92) for BC, and 0.21 (95% CI 0.09-0.46) for CC.
Homosexuals/bisexuals were more likely to be diagnosed with any cancer with ORs of 1.64
(95% CI 1.06-2.54) in women only and 1.50 (95% CI 1.11-2.03) in men and women combined.
Conclusions: Homosexuals/bisexuals in the US may be less likely to undergo screening of gender-
specific prevalent malignancies, including PCa, BC, and CC. The implementation of cancer screen-
ing among SMs should be improved. Research Sponsor: None.
Logistic multivariable regression models assessing associations with prostate, breast, and
cervical cancer screening.
                                             Men only -    Women only - Women only -
                                             PSA testing   Mammogram      Pap Test
                                            OR P value OR P value           OR     P value
Orientation (Gay/Bisexual vs                0.61 0.030 0.52 0.025           0.21   ,0.001
  Heterosexual)
Age (continuous)                             1.11 ,0.001 1.15 ,0.001 1.04 ,0.001
Smoking status (Never smoked reference)       -     -      -    -      -     -
  Current smoker                            0.61 0.020 0.74 0.127    2.21 0.050
  Former smoker                             0.91 0.422 0.96 0.801    4.45 0.006
Regular primary care provider (Yes vs No)   2.87 ,0.001 1.07 0.624   2.31  0.001
Health insurance (Yes vs No)                2.32 0.001 1.88 0.013    0.68  0.381
Ever had cancer (No vs Yes)                 2.18 ,0.001 0.62 0.072 0.085 0.752

          © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
PROSTATE CANCER - LOCALIZED

199                                                                                                    Poster Session

Factors influencing noncompletion of radiotherapy among men with localized prostate cancer.

Edward Christopher Dee, Vinayak Muralidhar, Melaku A Arega, Amar Upadhyaya Kishan, Daniel Eidelberg Spratt,
Robert Timothy Dess, Martin T. King, Sybil Sha, Patricia Mae G Santos, Santino Butler, Nina Niu Sanford,
Paul L. Nguyen, Brandon Arvin Virgil Mahal; Harvard Medical School, Boston, MA; Brigham and Women’s Hospital, Boston,
MA; Department of Radiation Oncology, University of California, Los Angeles, CA; Memorial Sloan Kettering Cancer Center,
New York, NY; University of Michigan, Ann Arbor, MI; Dana-Farber Cancer Institute/Brigham and Women’s Hospital, Boston,
MA; Dartmouth College Geisel School of Medicine, Hanover, NH; Department of Radiation Oncology, Memorial Sloan Kettering
Cancer Center, New York, NY; University of Texas Southwestern Medical Center, Dallas, TX; Dana-Farber Cancer Institute,
Brigham and Women’s Hospital, Harvard Medical School, Boston, MA; Department of Radiation Oncology, University of Miami
Miller School of Medicine, Miami, FL

Background: Treatment non-completion may occur with radiotherapy (RT), especially with
protracted treatment courses such as RT for prostate cancer, and may affect the efficacy of
RT. For men with localized prostate cancer managed with primary RT, we evaluated associations
between rates of treatment non-completion and RT fractionation schedules. Methods: The Na-
tional Cancer Database identified men diagnosed from 2004-2014 treated with primary RT.
Patients receiving 180cGy/fraction (conventional), 200cGy/fraction (conventional), 250cGy/
fraction (moderate hypofractionation), and 300cGy/fraction (moderate hypofractionation) were
defined as having completed radiotherapy if they received $40 fractions, $37 fractions, $28
fractions, and $19 fractions, respectively. Stereotactic body radiotherapy (SBRT) was defined as 5-
8 fractions of 600-800cGy/fraction. Odds ratios compared rates of treatment noncompletion,
adjusting for various sociodemographic covariates. Propensity-adjusted multivariable Cox regres-
sion assessed the association between treatment completion and overall survival. Results: Of
93,079 patients, 90.5% (N = 84,260) received conventional fractionation, 2.3% (N = 2,181)
received moderate hypofractionation, and 7.1% (N = 6,638) received SBRT. Rates of non-
completion were 10.0% (N = 8,406) among patients who received conventional fractionation,
7.5% (N = 163) among patients who received moderate hypofractionation, and 1.7% (N = 115) among
patients who received SBRT (OR versus conventional: 0.214, 95%CI 0.177-0.258, P , 0.001). The
rate of non-completion among 15,417 African American patients was 11.8%, compared to 8.8%
among 74,189 white patients (OR 1.39, 95%CI 1.31-1.47, P , 0.001). On subgroup analysis, the
disparity in non-completion persisted for conventional fractionation (12.4% vs. 9.4%, OR 1.36, 95%
CI 1.29-1.44, P , 0.001) and moderate hypofractionation (13.6% vs. 6.6%, OR 2.24, 95%CI 1.52-
3.29, P , 0.001), but not for SBRT (2.0% vs. 1.6%, OR 1.25, 95%CI 0.76-2.06, P = 0.384). Non-
completion was associated with worse survival on propensity-adjusted multivariate analysis (HR
1.37, 95%CI 1.31-1.43, P , 0.001). Conclusions: SBRT was associated with lower rates of RT non-
completion among men with localized prostate cancer. African American race was associated with
greater rates of treatment non-completion, although the disparity may be decreased among men
receiving SBRT. Research Sponsor: Prostate Cancer Foundation (PCF)Other Foundation, Other
Government Agency.

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
PROSTATE CANCER - LOCALIZED

200                                                                                                      Poster Session

The impact of telemedicine on patient-reported outcomes in urologic oncology.

Adam John Gadzinski, Isabelle O. Abarro, Blair Stewart, John L. Gore; University of Washington, Seattle, WA

Background: Nearly 20% of Americans live in rural communities. These individuals face barriers to
accessing cancer care, including prevalent poverty and substantial travel burden to seeing cancer
providers. We aimed to assess the impact of a rurally focused telemedicine program on patient
outcomes in our urologic oncology outpatient clinic. Methods: We prospectively identified patients
from rural Washington State, or who lived outside Washington, with a known or suspected
urological malignancy being evaluated at the University of Washington Urology Clinic via an in
person clinic or a telemedicine appointment. Patients were invited to complete a post-visit survey
that assessed satisfaction, travel time, costs, and work absenteeism. We compared patient-
reported outcomes between those seen as in-person versus telemedicine visits. Results: We
invited 1453 eligible patients from August 2019–July 2020 to participate; 615 patients (42%)
completed the survey. 198 patients had in person visits and 417 had telemedicine visits. Median age
was 68, 89% were male, and 73% were white. 525 patients (85%) were from Washington; the
remainder resided out-of-state. Patients were being evaluated for prostate cancer (62%), kidney
cancer (14%), urothelial cancer (22%), and testis cancer (2%). Patient-reported outcomes are
displayed in Table. Twenty-two patients coming for in-person visits (11%) paid $ $1000 in total
travel costs. No differences were noted in patient satisfaction between in-person and telemedicine
visit types. Conclusions: Patients traveling to our clinic from out-of-state and rural Washington
incur significant travel time, costs, and time away from work to receive outpatient urologic cancer
care. Telemedicine provides a medium for cancer care delivery that eliminates the significant
travel burden associated with in-person clinic appointments. Research Sponsor: Conquer Cancer
Foundation of the American Society of Clinical Oncology, Other Foundation.
                                                In person Telemedicine
                                                 n = 198     n = 417     p
One-way travel time (min, median [IQR])       197 (146-300) 15 (0-65)  ,0.001
One-way travel distance (miles, median [IQR]) 123 (80-335)   0 (0-30)  ,0.001
Total travel costs ($, median [IQR])          100 (40-425)   0 (0-9)   ,0.001
Air travel, n (%)                                42 (21%)   2 (,1%)    ,0.001
Hotel stay, n (%)                                58 (30%)    8 (2%)    ,0.001
Days off work (median [IQR])                      0 (0-1)    0 (0-0)   ,0.001

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PROSTATE CANCER - LOCALIZED

201                                                                                                      Poster Session

Racial disparities in depression incidence, management, and mortality after prostate cancer
diagnosis.

Ravi Bharat Parikh, Joseph J. Gallo, John Cashy, Kyle William Robinson, Vivek Narayan, Yu-Ning Wong,
Ravishankar Jayadevappa, Sumedha Chhatre; University of Pennsylvania, Philadelphia, PA; Johns Hopkins Bloomberg
School of Public Health, Baltimore, MD; Corporal Michael J. Crescenz VA Medical Center/University of Pennsylvania,
Philadelphia, PA; Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA; Fox Chase Cancer Center, Philadelphia, PA

Background: Depressive disorder is a common cause of morbidity among men with prostate
cancer (PC) and may contribute to known racial disparities in PC outcomes. We estimated the
incidence, management, and impact of depressive disorder (depression) on overall mortality
among African American (AA) and non-Hispanic White (W) Veterans with localized PC. Methods: In
this retrospective cohort study, we used linked administrative, survey, and electronic health record
data from the Veterans Health Administration (VA) Corporate Data Warehouse to identify AA and
W Veterans with no preexisting depression who were diagnosed with localized PC between January
1, 2004 and December 31, 2013. Patients were followed through December 31, 2019. The primary
outcomes were incident depression (defined from diagnosis codes and PHQ-2 and -9 screenings
between six months to five years after PC diagnosis), receipt of anti-depressant therapy, and all-
cause mortality. We used logistic and Cox regression models, adjusted for sociodemographic
factors, PSA, Gleason score, and prostate cancer treatment, to estimate associations with all
outcomes, using race-by-depression and race-by-treatment interaction terms to investigate racial
disparities. Results: Among 32,194 Veterans diagnosed with localized prostate cancer (median age
67 years [interquartile range [IQR] 62 to 73 years], median follow-up 9.9 years [IQR 8.0 to 12.1
years]), 8,177 (25.4%) were AA. Overall, 8,285 (25.7%) Veterans were diagnosed with depression
after PC diagnosis, and 2,525 (30.5%) of depressed Veterans received an antidepressant. Com-
pared to Veterans without depression, Veterans with incident depression had higher all-cause
mortality (adjusted hazard ratio [aHR] 1.30 [95% CI 1.25-1.35]). Race moderated all outcomes: AAs
were more likely than Ws to be diagnosed with depression. However, among those with depression,
AAs were less likely than Ws to receive an antidepressant. Interaction analyses showed that the HR
of all-cause mortality associated with depression among AAs was significantly greater than that of
Ws. Antidepressant receipt was not associated with improved mortality (aHR 1.05 [95% CI 0.97-
1.13]); this finding was not moderated by race. Conclusions: Depression was common among men
with prostate cancer within a large equal-access health care system, and African American men
had more adverse depression-related outcomes than White men. Identifying and managing inci-
dent depression should be a key target of efforts to improve prostate cancer outcomes and
disparities. Research Sponsor: Veterans Administration.
                                                 Adjusted odds or hazard
                                 Percentage          ratio (95% CI)
Incident depression (AA vs. W)   30.1 vs. 24.3         1.12 (1.05-1.19)
Antidepressant receipt (AA vs.   29.5 vs 30.1         0.84 (0.75-0.94)
   W)
Association between depression         -           1.35 (1.29-1.41) for AA;   1.17 (1.08-1.26)
   and mortality                                                                   for W

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PROSTATE CANCER - LOCALIZED

202                                                                                                       Poster Session

Understanding racial disparities in survival among U.S. veterans with localized high-risk
prostate cancer, 2004-2019.

Ravi Bharat Parikh, Sumedha Chhatre, Ruchika Talwar, Elina Medvedeva, John Cashy, S. Bruce Malkowicz, Vivek Narayan,
Ronac Mamtani, Kyle William Robinson, Ravishankar Jayadevappa; Harvard Medical School, Boston, MA; University of
Pennsylvania, Philadelphia, PA; Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA; Corporal Michael
J. Crescenz VA Medical Center/University of Pennsylvania, Philadelphia, PA; University of Pennsylvania Abramson Cancer
Center, Philadelphia, PA; Novartis, East Hanover, NJ

Background: Known racial disparities in prostate cancer outcomes between African-American
(AA) and non-Hispanic White (W) men may be ameliorated in the Veterans Health Administration
(VA), a large national equal-access health system. We examined factors contributing to racial
disparities in mortality among men with high-risk localized prostate cancer diagnosed in the VA.
Methods: In this retrospective cohort study, we used linked administrative, survey, and electronic
health record data from the Veterans Health Administration (VA) Corporate Data Warehouse to
identify AA and W Veterans who were diagnosed with high-risk localized PC, as defined by D’Amico
criteria, between January 1, 2004 and December 31, 2013. Patients were followed through
December 31, 2019. The primary outcome was all-cause mortality. We used hierarchical Cox
regression models, sequentially adjusting for covariates related to social determinants of health
(e.g. travel time, marital status), clinical factors at diagnosis (e.g. PSA, Gleason, comorbidity),
diagnosing facility, and prostate cancer treatment and adherence to American Cancer Society
survivorship care guidelines. Results: Among 21,338 Veterans receiving continuous VA-based
care (median age at diagnosis 66 years [interquartile range [IQR] 61-74]), 7,472 (28.7%) were AA,
9,404 (44.1%) died, and median follow-up was 8.4 years (IQR 6.1-11.1). After adjusting for all
covariates, AA Veterans (adjusted hazard ratio [aHR] 0.84, 95% confidence interval [CI] 0.83-
0.91) had improved overall survival compared to W Veterans. This association persisted in all
hierarchical regressions (see Table), was present in all pre-specified subgroups, and was strongest
among Veterans living in rural domiciles (aHR 0.70, 95% CI 0.64-0.77). Conclusions: AA Veterans
with high-risk localized prostate cancer had improved long-term survival compared to W Veterans,
which stands in contrast to prior studies among non-Veterans. Equal access to care may improve
racial disparities in prostate cancer, although future studies should clarify mechanisms of im-
proved survival for AA Veterans with prostate cancer in order to provide insights for ameliorating
outcome disparities in non-Veterans with prostate cancer. Research Sponsor: Veterans
Administration.
                                     Adjusted hazard ratio (95%
Model          Covariates                           CI)                     p-value
1         Univariate association              0.87 (0.83-0.91)              , 0.001
2               Model 1 +            Social determinants of health      0.81 (0.77-0.85)    ,
                                      (rurality, enrollment priority,                      0.001
                                     area deprivation index, marital
                                          status, driving time)
3       Model 2 + Clinical variables          0.89 (0.84-0.93)             , 0.001
        (Age, PSA, Gleason, T-stage,
               Comorbidity)
4         Model 3 + Facility fixed            0.85 (0.80-0.89)             , 0.001
                   effect
5        Model 4 + Process of care            0.84 (0.83-0.91)             , 0.001
           variables (treatment,
               survivorship)

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PROSTATE CANCER - LOCALIZED

203                                                                                                    Poster Session

Care received by rural and urban patients with newly diagnosed prostate cancer: Results from a
population-based prospective cohort.

Xinglei Shen, Ying Cao, Aaron J Katz, Deborah Usinger, Sarah Walden, Ronald C. Chen; University of Kansas Cancer Center,
Westwood, KS; University of Kansas Medical Center, Kansas City, KS; University of North Carolina, Chapel Hill, NC; University
of North Carolina at Chapel Hill, Chapel Hill, NC; University of Kansas, Kansas City, KS

Background: Rural residence is a source of disparity in cancer access and outcomes. It is not
known to what extent rurality affects access to care in patients with prostate cancer. Methods: The
North Carolina Prostate Cancer Comparative Effectiveness & Survivorship Study (NC ProCESS) is a
population-based cohort of newly-diagnosed prostate cancer patients. Patients were enrolled from
2011-2013 through collaboration with the state cancer registry at diagnosis and followed prospec-
tively. Urban/rural residence was defined by the rural urban continuum code (RUCC): 1-3 (urban)
and 4-9 (rural). Medical records were collected and abstracted for prostate cancer care received.
Individual-level sociodemographic information was collected by patient report. Results: Among
1,456 NC ProCESS participants with a median age of 65 years, 1089 were categorized as urban and
367 (25%) rural. This is a sociodemographically diverse cohort with 30.2% non-White (including
26.9% Black), 34.1% with high school education or less, and 37.3% with household income , =
$40,000. The distance to travel for diagnostic scans was greater for rural patients (miles): CT (7.5
urban vs 17.1 rural, p = 0.07), MRI (8.1 vs 12.0, p = 0.04) and bone scan (6.8 vs 14.1, p = 0.009).
However, there was no difference in the percent of patients who underwent CT (15.9% urban vs
12.8% rural, p = 0.15), MRI (7.8% vs 8.2%, p = 0.81) and bone scan (15.9% vs 19.4%, p = 0.13); or the
percentage of patients with high risk or metastatic disease who had any staging scan (64.2% vs
66.6% p = 0.8). While all patients consulted with a urologist, rural patients were less likely to have
had consultation with a radiation oncologist (42.4% vs 35.8%, p = 0.04). Rural patients were also
more likely to report that treatment was more difficult due to travel, including robotic prosta-
tectomy (6.8% vs 13.9% p = 0.001) and radiation therapy (8.01% vs 16.07%, p = 0.001). In patients
with low risk cancer, rural patients were more likely to have reported treatment at 12 months
(68.2% vs 58.7% p = 0.04) instead of surveillance or observation. For high risk patients, both rural
and urban patients reported high rates of treatment by 3 months (96.3% vs 91.3%, p = 0.40). After
adjustment for age, income, race, education and insurance, rural residence was associated with
increased likelihood of receiving treatment at 1 year (OR 1.54, CI 0.99 – 2.39) in low risk patients, but
not associated with receiving treatment at 3 months (OR 3.63, CI 0.24 -54.5) among high risk
patients. Conclusions: In a population-based cohort, rural patients with prostate cancer have
greater barriers such as travel distance, but similar proportions of rural and urban patients
received staging scans and timely treatment for high-risk prostate cancer. Rural patients were less
likely to receive multidisciplinary consultation prior to treatment, and were less likely to have
surveillance for low risk disease. Research Sponsor: PCORI.

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PROSTATE CANCER - LOCALIZED

204                                                                                                    Poster Session

Utilization and survival outcomes between definitive versus conservative treatments among
elderly men with high-risk prostate cancer.

Sagar Anil Patel, Hiram Alberto Gay, Jeff M. Michalski, Brian Christopher Baumann, Randall Brenneman,
Bruce Warren Hershatter, Ashesh B. Jani, Benjamin Walker Fischer-Valuck; Winship Cancer Institute of Emory University,
Atlanta, GA; Washington University School of Medicine, Department of Radiation Oncology, St. Louis, MO; Department of
Radiation Oncology, Washington University School of Medicine, St. Louis, MO; University of Pennsylvania, Department of
Radiation Oncology, Philadelphia, PA; The Emory Clinic, Atlanta, GA; Department of Radiation Oncology, Emory University
School of Medicine, Atlanta, GA

Background: Prostate cancer (PCa) is the second leading cause of cancer death in men . 80 years
old. However, studies have shown that older men are less likely to undergo curative treatment for
localized PCa, possibly due to competing comorbidities or inability to accurately estimate life
expectancy. Herein, we investigate utilization trends and survival outcomes amongst guideline-
supported treatment options in elderly men with high-risk PCa in the United States. Methods:
Men $ 80 years diagnosed with high-risk PCa (cT3-4 or Gleason 8-10 or PSA . 20) between 2004-
2016 were analyzed from the National Cancer Database. Those missing risk-stratification or
treatment data were excluded. Eligible patients were grouped based on their primary treatment
modality: no treatment (observation), androgen deprivation therapy (ADT) alone, radiation ther-
apy (RT) alone, RT + ADT, or radical prostatectomy (RP). Cochran-Armitage was used to evaluate
treatment trends over time, and multivariable logistic regression was used to identify sociodemo-
graphic predictors of treatment. Overall survival (OS) between treatments was evaluated using
Kaplan-Meier, log-rank, and multivariable Cox proportional hazards. Results: With a median follow
up of 42 months, 19,920 men were eligible for analysis. The most utilized treatment modality was
RT+ADT (37.2%), followed by ADT alone (29.4%), observation (23.9%), RT alone (7.8%), and RP
(1.7%). There was a significant increase in use of RT+ADT and RT alone (p , 0.001) and decrease in
use of ADT alone and observation (p, 0.001); no change was seen in RP use. There was no OS
difference between observation versus ADT alone (aHR 1.04, 95% CI 0.99-1.09, p = 0.11). Definitive
local treatment was associated with improved OS compared to ADT alone (RT+ADT: aHR 0.48,
95% CI 0.46-0.50, p , 0.0001; RT alone: aHR 0.54, 95% CI 0.50-0.59, p , 0.0001; RP: aHR 0.50,
95% CI 0.42-0.59, p , 0.0001). Black men and uninsured status were independently associated
with lower likelihood of undergoing definitive treatment (i.e. RT+ADT, RT, or RP). Conclusions: For
men $ 80 years old with high-risk PCa in this large US registry, definitive local therapy using RT +/-
ADT or RP was associated with a 50% reduction in overall mortality compared to observation or
ADT alone. Less than half of men in this time period underwent a definitive treatment, and Black
and uninsured men remained at particularly high risk of undertreatment. Research Sponsor: None.

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PROSTATE CANCER - LOCALIZED

205                                                                                                       Poster Session

Association between percentage of positive biopsy cores and risk of pelvic lymph node
involvement in prostate cancer.

David Dewei Yang, Edward Christopher Dee, Melaku A Arega, Paul L. Nguyen, Peter F. Orio, Martin T. King,
Benjamin Harris Kann, James B. Yu, Kiri Cook, Ting Martin Ma, Amar Upadhyaya Kishan, Vinayak Muralidhar; Harvard
Radiation Oncology Program, Boston, MA; Harvard Medical School, Boston, MA; Dana-Farber Cancer Institute, Brigham and
Women’s Hospital, Harvard Medical School, Boston, MA; Dana-Farber Cancer Institute, Boston, MA; Dana-Farber Cancer
Institute/Brigham and Women’s Hospital, Boston, MA; Brigham and Women’s Hospital/ Dana Farber Cancer Institute, Boston,
MA; Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT; UCLA School of Medicine, Los Angeles,
CA; UCLA, Los Angeles, CA; Department of Radiation Oncology, University of California, Los Angeles, CA; Brigham and
Women’s Hospital, Boston, MA

Background: Commonly used tools for predicting the risk of pelvic lymph node involvement (LNI)
in prostate cancer often do not incorporate information on the percentage of positive biopsy cores
(PPB). To better inform the use of elective nodal irradiation in the definitive treatment of prostate
cancer, we examined the association between PPB and risk of pathologic pelvic LNI in men with
prostate cancer who underwent radical prostatectomy (RP). Methods: We identified 109,577 men
from the National Cancer Database who were diagnosed in 2010-2015 with cN0M0 prostate cancer,
had 6-24 cores sampled at biopsy, and underwent RP with pathologic nodal evaluation. Multivar-
iable logistic regression was used to examine the association between PPB and the likelihood of
having $1 positive pelvic lymph node, adjusting for other known clinicopathologic prognostic
variables. Results: Overall, 4.0% (4,340) of the cohort was found to have pelvic LNI at the time of
RP. Higher PPB was associated with an increased risk of pelvic LNI (adjusted odds ratio [AOR] 1.75
for 25.1-50.0% PPB, 2.63 for 50.1-75.0% PPB, and 4.49 for 75.1-100.0% PPB vs. #25.0% PPB, all
P,0.001). Notably, men with Gleason 8 disease and #25.0% PPB only had a 3.6% risk of pelvic LNI,
whereas men with Gleason 9-10 disease and 75.1-100.0% PPB had a 32.6% risk (Table). Other
factors associated with the likelihood of pelvic LNI included a higher biopsy Gleason score (AOR
1.43 for Gleason 8 and 2.84 for Gleason 9-10 vs. Gleason 4+3, both P,0.001), more advanced
clinical tumor stage (AOR 1.48 for cT2, 1.97 for cT3, and 3.87 for cT4 vs. cT1, all P,0.001), and a
higher PSA (AOR 1.90 for 10.0-19.9 ng/mL, 2.40 for 20.0-39.9 ng/mL, and 2.60 for $40.0 ng/mL
vs. ,10.0 ng/mL, all P,0.001), but not more advanced age (AOR 0.98 for .62 years [median]
vs. #62 years, P=0.59) or black vs. white race (AOR 0.99, P=0.92). Conclusions: There was a
statistically significant and clinically relevant association between increasing PPB and a higher risk
of pelvic LNI. As the ongoing RTOG 0924 randomized trial matures, clinicians should consider
incorporating information on PPB in determining which patients with prostate cancer may benefit
from receiving radiation therapy to the pelvic lymph nodes. Research Sponsor: None.
The risk of pelvic lymph node involvement by percentage of positive biopsy cores (PPB) and
biopsy Gleason score.
                   Gleason 6    Gleason 3+4     Gleason 4+3    Gleason 8    Gleason 9-10
PPB   £25.0%          0.1%          0.6%            2.6%          3.6%           8.6%
PPB   25.1-50%        0.3%          1.1%            4.6%          7.2%          13.3%
PPB   50.1-75.0%      0.2%          1.9%            7.8%         11.9%          18.9%
PPB   75.1-100%       0.3%          4.0%            13.1%        17.8%         32.6%

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PROSTATE CANCER - LOCALIZED

206                                                                                                     Poster Session

Considerations for active surveillance in select Gleason grade group 2 patients: A preliminary
study.

Jillian Egan, Cheyenne Williams, Nabila Khondakar, Luke P. O’Connor, Michael Daneshvar, Nitin Yerram, Maria Merino,
Peter L. Choyke, Bradford Wood, Baris Turkbey, Peter A. Pinto; Urologic Oncology Branch, National Cancer Institute, National
Institutes of Health, Bethesda, MD; Laboratory of Pathology, National Cancer Institute, National Institutes of Health,
Bethesda, MD; Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD; Center for
Interventional Oncology, National Cancer Institute, National Institutes of Health, Bethesda, MD

Background: While active surveillance (AS) has become the preferred management strategy for
patients with NCCN very-low and low risk prostate cancer, its use in the setting of intermediate risk
disease continues to be controversial. Current guidelines state that AS can be considered in
favorable intermediate risk disease, but data on outcomes in this cohort of patients is lacking. We
aim to report on our experience with AS of Gleason grade group (GG) 2 at the National Cancer
Institute (NCI)/National Institutes of Health (NIH). Methods: Our IRB-approved, institutional
database was reviewed for men who enrolled on our AS protocol at NIH with GG2 disease from
2007-2020. All patients received MRI-targeted and systematic biopsy at the time of enrollment,
diagnosing or confirming GG2 disease. MRI and PSA were performed annually, and majority of
patients underwent annual combined MRI targeted and systematic prostate biopsy. If PSA and MRI
were stable, annual biopsy was postponed in several patients based on their preference. Differ-
ences in PSA and PSAD at enrollment on AS and at progression were compared using Wilcoxon
signed rank test. P value , 0.05 was considered significant. Results: 98 patients with GG2 disease
enrolled in AS at NIH. Average age at enrollment was 64 years old and the majority of patients were
Caucasian. 36/98(37%) of these patients progressed to GG3 or higher while on AS. Median PSA at
time of progression was significantly higher than at the time of enrollment on AS (5.2 [IQR 4.0-8.9]
vs 8.5 [IQR 5.8-10.9], z = -3.12, p , 0.01). PSAD was also significantly higher at time of progression
(0.12[IQR 0.1-0.16] vs 0.13[IQR 0.10-0.22], z = -2.65, p , 0.01). Highest PIRADS score on MRI was
largely unchanged. Median time to progression was 71 months. The majority of patients progressed
to GG3, and progression was the trigger for definitive treatment. All patients were alive at the end
of the follow up period. Conclusions: AS is a reasonable option for compliant patients diagnosed
with GG2 prostate cancer. While a significant percentage of these men will progress on AS, they do
so at a median of 71 months, avoiding treatment-related harms of definitive therapy for over 5
years. Further research with larger sample sizes are needed to better evaluate the oncologic
outcomes of AS for GG2 disease, as well as predictors of more aggressive disease that may be
better served with upfront definitive treatment. Research Sponsor: U.S. National Institutes of
Health.
                At Active Surveillance   At time of progression
Median PSA                5.2                       8.5           Z = -3.12
[IQR]                  [4.0-8.9]                [5.8-10.9]        p , 0.01
Median PSAD               0.12                      0.13          Z = -2.65
[IQR]                 [0.10-0.16]               [0.11-0.22]       p , 0.01

        © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
PROSTATE CANCER - LOCALIZED

207                                                                                                    Poster Session

Bilateral disease and risk of prostate cancer progression in an active surveillance cohort.

Nabila Khondakar, Luke P. O’Connor, Cheyenne Williams, Michael Daneshvar, Jillian Egan, Nitin Yerram, Brad Webster,
Maria Merino, Peter L. Choyke, Bradford Wood, Baris Turkbey, Peter A. Pinto; Urologic Oncology Branch, National Cancer
Institute, National Institutes of Health, Bethesda, MD; National Institutes of Health, Bethesda, MD; Laboratory of Pathology,
National Cancer Institute, National Institutes of Health, Bethesda, MD; Molecular Imaging Program, National Cancer Institute,
National Institutes of Health, Bethesda, MD; Center for Interventional Oncology, National Cancer Institute, National
Institutes of Health, Bethesda, MD

Background: Active surveillance (AS) is considered the standard of care for managing patients
with low-risk prostate cancer. Identifying risk factors for disease progression on AS can improve
risk stratification. As previously described, the presence of bilateral disease may affect disease
progression. Current systematic biopsy techniques inadequately predict presence of bilateral
disease. We hypothesize that combined mpMRI-guided fusion biopsy and systematic biopsy will
improve detection of bilateral disease. Methods: Our institutional database of patients referred for
AS from 2007-2020 was queried. All AS patients received combined 12-core systematic biopsy and
mpMRI-Fusion biopsy (Cbx), and those with Gleason Grade group 1 (GG1) on confirmatory Cbx were
included. Cox regression analysis identified baseline characteristics associated with AS progres-
sion, defined as progression to GG $ 2. The distributions of GG and National Comprehensive Cancer
Network (NCCN) risk categories were also compared. Results: 103 patients with prostate cancer
and at least one follow-up biopsy at our institution were included in the analysis. 30% (31/103) had
bilateral disease and 70% (72/103) had unilateral disease. On univariable and multivariable
analysis, both PSAD (univariable HR = 1.6; 95% CI: 1.1-2.2; multivariable HR = 1.7; CI: 1.2-2.5)
and presence of bilateral disease (univariable HR = 2.2; 95% CI: 1.3-4.0; multivariable HR = 2.2; 95%
CI: 1.2-4.0) at time of confirmatory biopsy were significantly associated with AS progression.
On Kaplan-Meier analysis, median time from Cbx to AS progression $ GG2 for the whole cohort
was 52 months (95% CI: 44 - 68). The median time to progression for patients with unilateral
and bilateral disease was 68 months and 52 months, respectively (log-rank test, p = 0.0055).
Bilateral disease was marginally associated with receiving an NCCN score of high or very high on
upgraded biopsy (RR: 3.16, 95% CI: 1.004-9.932). NCCN score at time of confirmatory biopsy was
not associated with progression. However, NCCNs scores and GG at time of progression were
higher among patients with bilateral disease (p = 0.015 and p = 0.024). Ultimately, use of combined
biopsy resulted in 16.1% more bilateral cancers detected when compared to systematic biopsy.
Conclusions: Detection of bilateral disease using combined biopsy was significantly associated
with disease progression in patients on AS. Notably, combined biopsy resulted in greater detection
of bilateral disease than systematic biopsy alone. Identifying presence of bilateral disease using
combined biopsy could ultimately contribute to management decisions in patients on AS. Research
Sponsor: U.S. National Institutes of Health, Foundation for the NIH.

       © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
PROSTATE CANCER - LOCALIZED

208                                                                                                      Poster Session

MRI-guided fusion biopsy of the prostate resection bed among post-radical prostatectomy
patients with rising PSA.

Cheyenne Williams, Nabila Khondakar, Michael Daneshvar, Luke P. O’Connor, Jillian Egan, Nitin Yerram, Alexis Rompre-
Brodeur, Jeunice Owens-Walton, Maria Merino, Peter L. Choyke, Bradford Wood, Baris Turkbey, Peter A. Pinto; Urologic
Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD; Laboratory of Pathology, National
Cancer Institute, National Institutes of Health, Bethesda, MD; Molecular Imaging Program, National Cancer Institute, National
Institutes of Health, Bethesda, MD; Center for Interventional Oncology, National Cancer Institute, National Institutes of
Health, Bethesda, MD

Background: Following treatment of prostate cancer with radical prostatectomy (RP), biochemical
recurrence (BCR) can be detected with elevated PSA. This may be attributed to either cancer
recurrence or retained benign prostatic gland tissue. Options for detecting malignancy after RP
currently entail diagnostic imaging and biopsy with transrectal ultrasound (TRUS). TRUS alone has
limited accuracy in detecting recurrence in the prostate bed. MRI fusion-guided biopsy (Fbx) may
be a more accurate method of detecting post-RP local recurrence. We hypothesize that Fbx for
diagnosing benign versus malignant recurrence in the prostate bed is feasible and produces
clinically meaningful results. Methods: Our institutional database was queried for patients who
received RP and demonstrated BCR between February 2015 and July 2020. All patients with
evidence of prostate bed recurrence on mpMRI were included in this analysis. Cancer detection via
mpMRI-guided fusion biopsy using the UroNav platform was evaluated and patient variables
including final Gleason Grade group (GG), margin involvement, PSA at BCR, and prostate bed lesion
size were analyzed with univariate logistic regression. Results: 40 patients (median age = 68) with
BCR underwent post-RP mpMRI. 25/40 (62.5%) patients had MRI-visible lesions, and among those,
17/25 (68%) patients underwent Fbx of the prostate bed. 15/17 (88.2%) Fbxs detected prostate
tissue (either benign or cancer), 11/17 (64.7%) contained cancer, and 4/17 (23.5%) contained
benign prostate glands. Median cores per biopsy was 4 (IQR 4-6). Among the 83 cores obtained, 57
(68.6%) cores contained prostate gland tissue and 26 (31.3%) contained fibromuscular tissue. Of
those 57 with gland tissue, 33 (57.9%) cores contained cancer, and 24 (42.1%) contained benign
prostate tissue. Among patients with benign biopsies, none had further evidence of metastasis at
median follow-up of 13.5 months after Fbx and 182 months after RP. On final RP pathology, 4
patients had GG1 disease, 4 had GG2, 4 had GG3, 2 had GG4, and 3 had GG5. 6/17 (35%) patients had
positive RP margins. Median prostate bed lesion size was 1.3 cm (IQR 0.9-1.5). Prostate bed lesion
size (cm) was the only variable significantly associated with cancer on Fbx (OR = 2.20, 95% CI:1.29-
3.76, p = 0.011). Conclusions: mpMRI-Fbx is a feasible method for reliably targeting prostate bed
lesions. With this technique, we found improved accuracy for biopsy-proven recurrence in the
prostate bed. This technique will help direct treatment planning of salvage therapies among
patients with detectable PSA post-RP. Research Sponsor: U.S. National Institutes of Health,
Foundation for the National Institute of Health.
                                   Positive Fbx of Prostate Bed
                                            OR (95% CI)                p
Grade Group 1 at RP                        1.14 (0.65-2.02)          0.65
Grade Group 2                              0.83 (0.47-1.45)           0.51
Grade Group 3                              0.83 (0.47-1.45)           0.51
Grade Group ‡4                              1.24(0.7-2.09)            0.42
Margin Involvement                          1.03(0.62-1.71)           0.91
PSA at BCR                                 0.89 (0.59-1.36)           0.61
Prostate bed lesion size (cm)              2.20(1.29-3.76)           0.011*

         © 2021 American Society of Clinical Oncology. Visit gucasym.org and search by abstract for disclosure information.
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