(UroToday.com) The 2023 ASCO annual meeting included a prostate cancer session, featuring a presentation by Dr. Rigoberto De Jesus Pizarro discussing treatment and survival of de novo metastatic hormone sensitive prostate cancer (mHSPC) among African American US Veterans. Combinations of ADT plus docetaxel or androgen signaling inhibitors (abiraterone, enzalutamide, etc.) have revolutionized treatment of mHSPC, particularly for high volume disease. However, little is known about the use of and outcomes of combination therapy in African Americans with de novo mHSPC, due to their lack of representation in clinical studies. This study evaluated the patient characteristics, treatment, and survival in a cohort of US veterans with mHSPC with equal access to treatment under the Veterans Affairs Health System (VA).
Veterans with mHSPC were identified from 2014-2021 in the VA using the initial pathological diagnosis of prostate cancer with SEER stage ‘distant’ and first ADT initiated within 1 month prior and 3 months after diagnosis. Therapies including docetaxel or androgen signaling inhibitors were collected if initiated from 1 month prior to 4 months after ADT. Additional information at the time of diagnosis was collected including PSA, race from VA enrollment, and Charlson Comorbidity Index (CCI). Median survival was obtained for each group and stratified by PSA level >100 ng/mL. Chi-square and ANOVA testing were used differences in survival (OS) were assessed by log-rank testing.
There were 4,248 veterans with de novo mHSPC identified, 1,138 (26.8%) were African Americans, and 3.110 (73.2%) white. Black veterans were younger (70.8 vs. 74.8 years, p<0.001) and had higher median PSA (183 vs. 86.3 ng/mL, p<0.001) with similar mean CCI (4.4 vs. 4.4, p=0.78):
African American veterans were likely to have a PSA >100 ng/mL at diagnosis (61.6% vs. 46.1%, p<0.001) and to receive combination therapy than white veterans (36.8% vs. 32.7%, p=0.01). The median OS among African Americans and white veterans was similar (32.5 months vs. 32.1, p=0.75):
In 2,120 veterans with PSA>100 ng/mL (a surrogate for higher volume disease), African Americans veterans were more likely to receive combination therapy (39.5% vs. 32.9%, p=0.003) without differences in survival in African American veterans compared to white (31.0 vs. 26.9 months, p=0.18):
Dr. De Jesus Pizarro concluded his presentation by discussing treatment and survival of de novo mHSPC among African American US Veterans with the following take-home points:
- In an equal access health care system, African American veterans had similar survival to white veterans despite having double the PSA levels, reflecting higher risk disease
- African Americans presented 3.5 years younger and are likely treated with doublet therapy
- The differences in the age of onset and burden of disease highlight persistent differences in populations with mHSPC
- Further investigations to understand environmental, social, and tumor factors are warranted to explain these disparities
Presented by: Rigoberto De Jesus Pizarro, MD, Washington University School of Medicine, St. Louis, MO
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 2 – Tues, June 6, 2023.