Approach to treatment of metastatic hormone-sensitive prostate (mHSPC) cancer among cooperative oncology groups (CCTG, SWOG, and Alliance) in North America.

Abstract

263 Background: Randomized clinical trials have demonstrated the efficacy of both doublet (androgen deprivation therapy (ADT) + androgen receptor pathway inhibitor (ARPi)) and triplet (ADT + ARPi + docetaxel) regimens in the treatment of mHSPC. However, the optimal clinical setting for each approach remains unclear. We surveyed genitourinary oncologists to identify their practice patterns with respect to systemic therapy for mHSPC. Methods: A 13-question survey was distributed to clinicians associated with the Canadian Clinical Trials Group (CCTG), SWOG, and Alliance for Clinical Trials in Oncology between March 2024 and June 2024. We collected data on clinician specialty, practice setting, location, years of clinical experience, and approach to management for patients with mHSPC. Results: 542 responses were solicited, and 104 (19%) surveys were completed. 24 respondents were from Canada (CCTG) and 80 were from the United States (47 SWOG, 33 Alliance). 88% (92/104) respondents indicated that less than 50% of their mHSPC patients are started on triplet therapy (Table). The most important factors when considering the use of doublet vs. triple therapy were volume of disease (88/104, 85%) and patient comorbidities (82/104, 79%). Physicians favored triplet therapy in high volume, de novo (95/104, 91%) or recurrent (70/104, 67%) disease, but not in low volume, de novo (2/104, 2%) or recurrent (2/104, 2%) disease. The greatest barriers to triplet therapy were toxicity concerns (75/104, 72%) and patient factors (66/104, 63%). In the scenario where prostate specific antigen (PSA) remained at 4 ng/ml after 6 months of doublet therapy, 77% (80/104) would not make any changes, while 23% (24/104) could consider additional intensification strategies, including clinical trial enrollment. In the scenario where PSA was undetectable after two years on doublet therapy, 63% (65/104) would continue therapy without de-escalation, while 37% (38/104) would consider deintensification, and 1 declined to answer. Responses were concordant between American and Canadian participants. Conclusions: North American genitourinary oncologists consider disease volume, patient comorbidities, and toxicity when opting for doublet vs. triplet therapy, and feel there is a role to explore PSA-based de/intensification strategies in future clinical trials. Alliance (n = 33) SWOG (n = 47) CCTG (n = 24) Total (n = 104, %) Specialty Medical Oncology 32 39 24 95 (91%) Radiation Oncology 0 4 0 4 (4%) Surgical Oncology 0 3 0 3 (3%) Other 1 1 0 2 (2%) Practice setting Academic 31 41 24 96 (92%) Private 0 1 0 1 (1%) Other 2 5 0 7 (7%) Years from fellowship <5 years 11 8 6 25 (24%) 5-10 years 6 10 5 21 (20%) 10-20 years 8 15 9 32 (31%) >20 years 8 13 4 25 (24%) Other / Skipped 0 1 0 1 (1%) Percent of patients offered triplet therapy <10% 9 14 8 31 (30%) 11-30% 12 20 13 45 (43%) 31-50% 7 9 0 16 (15%) 51-75% 3 3 2 8 (8%) >76% 2 1 1 4 (4%)