Abstract 747: Racial differences in clinical outcome in patients treated for clinically localized prostate cancer by radical prostatectomy
Authors: Li Pin , Zhao Wei , Carskadon Shannon , Rogers Craig , Peabody James , Menon Mani , Chitale Dhananjay , Williamson Sean , Gupta Nilesh , Palanisamy Nallasivam 
Published: April 2023

Introduction: African Americans (AA) had a higher mortality from prostate cancer than Caucasian Americans (CA). The racial disparity in the outcome of prostate cancer is explained by socioeconomic factors. However, if equally accessible to standard care, whether AA with prostate cancer have an inferior outcome than CAs remains unknown. To understand the biochemical recurrence free survival (RFS) after radical prostatectomy in a racial disparity perspective, we analyzed a large cohort of patients and made important observations.

Method: AA (n=1020) and CA (n=1263) who received prostatectomy for prostate cancer were included. Their demographic and clinicopathologic characteristics were compared using the Chi-squared test and the Wilcox-rank test. RFS between AA and CA was compared using Kaplan-Meier curves with stratified log-rank test and cox-ph models. The Gleason grade across multiple biopsies was summarized by spaghetti plot and compared by linear mixed models.

Results: Compared with CA, AA were younger at the time of prostatectomy (60.5 vs 62 years), had higher pre-operative PSA levels (5.7 vs 5.3 ng/mL), were fewer with Gleason grade of 5 (7.9% vs 13.3%) and lymph node metastasis (6.1% vs 9.5%), and waited longer from biopsy to prostatectomy (3 vs 2.3 months)(all p &lt;.05). Of note, longer RFS (16 vs 15.6 years, p=0.005) and higher 5-year RFS rate (0.82 vs 0.71) were observed in AA than CA. AA had a better RFS than CA (Hazard Ratio=1.25, p=0.05) after adjusting known prognostic factors (Table 1). For those who had multiple biopsies before prostatectomy, Gleason grade increased with time for AA (0.15 per year, p=0.005), but not for CA (-0.11 per year, p=0.06).

Conclusion: Our data showed that contrary to common belief, AA had a better RFS than CA after receiving prostatectomy. This study further supported the underlying biological difference of prostate cancer between AA and CA that requires future studies to elucidate.

RFS Summary HR Race African American 1020 (44.7) - Caucasian 1263 (55.3) 1.25 (1.00-1.58, p=0.05) Pre-operative PSA (ng/mL) Mean (SD) 7.5 (9.0) 1.01 (1.01-1.02, p&lt;0.001) Tumor volume (%) Mean (SD) 14.9 (14.5) 1.01 (1.00-1.02, p=0.02) Gleason Grade Group 1 375 (16.7) - 2 1060 (47.2) 1.84 (1.05-3.22, p=0.03) 3 435 (19.4) 3.91 (2.20-6.94, p&lt;0.001) 4 129 (5.7) 4.10 (2.25-7.47, p&lt;0.001) 5 249 (11.1) 3.82 (2.10-6.96, p&lt;0.001) Tumor margins Positive 730 (32.0) 1.78 (1.43-2.13, p&lt;0.001) Lymph vascular invasion Present 274 (12.0) 1.50 (1.10-2.05, p=0.01)

Citation Format: Pin Li, Wei Zhao, Shannon Carskadon, Craig Rogers, James Peabody, Mani Menon, Dhananjay Chitale, Sean Williamson, Nilesh Gupta, Nallasivam Palanisamy. Racial differences in clinical outcome in patients treated for clinically localized prostate cancer by radical prostatectomy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 747.