(UroToday.com) The 2023 American Society of Clinical Oncology Genitourinary (ASCO GU) cancers symposium held in San Francisco, CA between February 16th and 18th was host to a prostate cancer poster session. Kelli Rasmussen, MS, presented the results of their group’s study evaluating the association of race with progression from non-metastatic to metastatic castrate-resistant prostate cancer (mCRPC) within the context of the Veterans Affairs (VA) health care system.
Androgen deprivation therapy remains the treatment backbone for patients with advanced prostate cancer. Inevitably, a significant portion of patients will progress to a castrate-resistant disease state. Using conventional imaging as the reference standard in this setting, patients will typically progress initially to a non-metastatic, followed by a metastatic castrate disease state. Sociodemographic predictors of progression from the nmCRPC to a mCRPC state remain unknown. While prostate cancer patients of racial/ethnic minority backgrounds are known to have disparately worse oncologic outcomes,1 the association between race and progression from nmCRPC to the more advanced mCRPC disease state remains unknown. The authors sought to evaluate this clinical question within the context of the equal access VA health care system.
This was a retrospective cohort analysis of patients with nmCRPC using the VA Clinical Cancer Registry (VACCR) and the VA Corporate Data Warehouse (CDW) databases. nmCRPC was defined using the following criteria:
- Evidence of a rising prostate-specific antigen (PSA), i.e., two consecutive increases in PSA concentration over a baseline value
- Evidence of ongoing testosterone suppression (serum testosterone level of ≤50 ng/dL (≤2.0 nmol/L)
- Absence of metastatic disease as evidenced in radiology reports using conventional imaging
NCCN-guideline recommended medications were identified by the authors, subsequently extracted from the CDW pharmacy dispensation records, and indexed at nmCRPC diagnosis. A time-to-event analysis using multivariable Cox proportional hazard modeling was used to evaluate the association between patient race and time to progression to mCRPC.
The authors identified 654,148 patients with prostate cancer receiving care at the VA between 2006 and 2021. 12,992 (2.0%) patients were identified as having nmCRPC, of which 7,323 (56%) were white, 3,671 (28%) black, 826 (6%) Hispanic, and 1,172 (9%) categorized as other. With regards to baseline demographic analyzed by race, Black men were younger (70 versus 74 years in White), whereas Hispanic men were older (75 years). Black nmCRPC patients had higher PSA (14.3 ng/ml) compared to White and Hispanic men (10.2 ng/mL and 10.4 ng/mL) at time of nmCRPC progression.
Similar treatment patterns were observed in all patients regardless of race; with ADT (60%), bicalutamide (24%), and finasteride (3%), the most frequently used first-line treatments. Notably, the mean time from nmCRPC to mCRPC was 27.5 days for white, 31.6 days for black, 27.6 for Hispanic, and 26.0 days for other patients. On multivariable cox analysis adjusting for the confounders of age, comorbidities, PSA doubling time, and treatment, both Black (HR: 0.85, 95% CI: 0.80 to 0.90, p<0.001) and Hispanic patients (HR: 0.70, 95% CI: 0.62 to 0.78, p<0.001) had significantly lower hazards of progression to mCRPC.
These results suggest that, within the context of an equal access/opportunity health care system such as the VA health care system, Black and Hispanic patients with nmCRPC have significantly lower hazards of progression from nmCRPC to mCRPC, compared to White men.
Presented by: Kelli Marie Rasmussen, MS, University of Utah School of Medicine, Salt Lake City, UT
Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2023 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, San Francisco, CA, February 16th – February 18th, 2023
References:
- Mahal BA, et al. Racial disparities in prostate cancer outcome among prostate-specific antigen screening eligible populations in the United States. Ann Oncol 2017;28(5):1098-1104.