Evolving real-world patterns of practice in metastatic castration-sensitive prostate cancer (mCSPC): The genitourinary research consortium (GURC) national multicenter cohort study.

Abstract

86 Background: Treatment options for patients with mCSPC have rapidly evolved with the introduction of androgen receptor axis targeted therapies (ARATs) and chemotherapy. The GURC cohort study is a phase 4, multicentre, non-interventional, longitudinal cohort study of Canadian men with advanced prostate cancer. We prospectively examined the evolving real world management and treatment patterns of patients with mCSPC, with a focus on treatment intensification beyond ADT and germline DNA damage repair (DDR) testing. Methods: Clinical management patterns, baseline patient characteristics, germline DDR alteration status, treatment intensification with ARATs (abiraterone acetate [AA], apalutamide [Apa], enzalutamide [Enza]) and chemotherapy within the mCSPC cohort were analyzed. Results: 204 patients with mCSPC were enrolled from 2018 to 2021 across 25 Canadian sites. The median age was 71 (range 64 - 77), median PSA at study entry was 24, 88% (158/180) of patients had de novo mCSPC, 69% (110/204) of patients had a Gleason Score > 7, and 4% (2/49) of the patients who received a germline testing harbored a germline DDR alteration (BRCA2 = 1, MUTYH/MEN1 = 1). The distribution of high and low volume mCSPC at study entry was 62% (118/189) and 37% (71/189), respectively. Overall, patients received ADT alone 27% (51/189), AA 45% (86/189), apalutamide 17% (33/189), docetaxel 8% (15/189), and enzalutamide 3% (6/189). Treatment intensification with ARATs/docetaxel was administered to 69% [141/189]) of patients. Patients treated with ADT alone had a significantly lower volume of disease at treatment initiation (low volume rates of 49% [24/49] in ADT alone vs 33% [47/143] in treatment intensified patients, p = 0.044). Among those receiving treatment intensification with ARATs/docetaxel, time to intensification was ≤ 3 months in 78.5 % (113/144). Conclusions: This cohort study demonstrates that patients with mCSPC continue to receive ADT alone and docetaxel over time, despite an ever-increasing list of accessible ARATs. Patients receiving ADT alone appear to have lower volume of disease. Germline DDR testing is not yet comprehensively performed. This underlines the real world need to provide greater education and resources to encourage ARAT treatment and genetic testing in this setting.