Real-world findings presented at the 2022 ASCO Annual Meeting suggest that despite the recent approval of several non-metastatic castration-resistant prostate cancer (nmCRPC) treatments that have demonstrated improved metastasis-free survival and quality of life, first-generation antiandrogens remain the predominant first-line (1L) treatment for nmCRPC patients. 

Prostate cancer (PC) is prevalent among U.S. veterans, being the most common cancer diagnosed among this group. With the recent approval of novel antiandrogens, the treatment landscape for nmCRPC has rapidly evolved. 

“Although there have been numerous clinical trials examining the safety and efficacy of these treatments, few studies have identified real-world treatment patterns among nmCRPC patients,” wrote Ahmad Sami Halwani, MD, University of Utah, Salt Lake City, UT, and colleagues. 

Using patient data from the Veterans Affairs (VA) Clinical Cancer Registry and the VA Corporate Data Warehouse (CDW), Dr Halwani and colleagues conducted a retrospective observational study on patients who were diagnosed with PC at the VA, and later developed nmCRPC. Treatments were extracted from CDW pharmacy dispensation records and were indexed at nmCRPC diagnosis. The criteria for patients with nmCRPC to be selected was: evidence present of rising PSA; evidence of ongoing androgen deprivation consisting of a serum testosterone level of ≤50 ng/dL (≤2.0 nmol/L); and no evidence of metastatic disease on radiology reports. 

Among the 12,549 patients who were diagnosed with nmCRPC and treated in the VA from 2006 to 2020, 7239 (58%) were White, 3386 (27%) were Black, 784 (6%) were Hispanic, and 1140 (9%) other, with a median age of 69 years at the age of PC diagnosis. A total of 4817 (38%) were residing in the South. 

Among the 7659 (61%) patients receiving 1L nmCRPC therapy, 5508 (72%) received bicalutamide, 621 (8%) ketoconazole, 563 (7%) abiraterone, 492 (6%) enzalutamide, and 242 (3%) flutamide. Bicalutamide remained the most frequently used 1L nmCRPC therapy throughout this study. The approval of abiraterone and enzalutamide in 2012 lead to a decline of 1L bicalutamide, going from 80% of patients in 2006 to 43% in 2020. Ketoconazole was the second most common 1L nmCRPC therapy. Among patients receiving 1L therapy, 2,244 (31%) received 2L therapy, and 708 (32%) of those who received 2L therapy received 3L therapy.

“To our knowledge, this is the largest real-world cohort of nmCRPC patients treated in a nationwide equal-access health care system,” concluded Dr Halwani and colleagues, adding, “Despite the recent approval of several nmCRPC treatments (apalutamide, darolutamide, enzalutamide) which have demonstrated improved metastasis-free survival and treatment-related quality of life, our real-world findings suggest that older, first-generation antiandrogens remain the predominant 1L treatment for nmCRPC patients.”

Source:

Halwani AS, Patil V, Morreall D, et al. Real-world treatment patterns among veterans with nonmetastatic castration-resistant prostate cancer (nmCRPC). Abstract presented at: ASCO Annual Meeting; June 3-7, 2022; Chicago, IL, and virtual. Abstract e17042.