Additional cycles of docetaxel in combination with androgen deprivation therapy (D-ADT) in metastatic hormone-sensitive prostate cancer (mHSPC): Efficacy and feasibility analysis.

Abstract

185 Background: Several phase III trials have assessed efficacy and safety of 6 cycles of docetaxel combined to androgen deprivation therapy (ADT). This is the current standard of care for a subgroup of patients. We aimed to assess whether treatment beyond 6 cycles of docetaxel prove to be more effective than the standard of care. Methods: We retrospectively analyzed patients with histologically confirmed adenocarcinoma of the prostate and radiologically proven metastatic disease from a large tertiary care center. All patients with mHSPC were treated in first line with ADT in combination with docetaxel (75 mg/m2) (D-ADT) intravenously on the first day of each 21-day cycle. A subset of patients was treated beyond the standard of 6 cycles. Clinical and pathological variables were analyzed, progression free survival on D-ADT (PFS1), progression free survival on subsequent therapy (PFS2) and overall survival (OS) were the endpoints analyzed by log- rank test. Results: Between 2018-2022 a total of 74 mHSPC patients were followed-up for a median time of 13.7 months. Mean age was 66.2 years (range 50.1-82.4), and 79.7% had GS≥8, 73% a CHAARTED high-volume and 76% LATITUDE high risk disease. 43 pts. were treated with ≤ 6 cycles (D-ADTstand) (2.4 % 1-2 cycles; 97.6 % ≥3 cycles; mean 5.3 cycles) and 31 were treated with >6 cycles docetaxel (D-ADTadd) (25.8 % 7-8 cycles; 74.2% ≥9-10 cycles, mean 9.2 cycles). No significant differences were observed in median PFS1 (12.4 vs. 13.7 mos.) and PFS2 (5.4 vs. 9.6 mos.). Median OS in the D-ADTstand group was 39.8 mos., median OS in the D-ADTadd group was not yet reached. Conclusions: While more than 6 cycles of D-ADT in mHSPC proved to be feasible without significant additional toxicity, efficacy is not superior compared to the standard of 6 cycles. Overall survival data is not mature yet, but the benefit of more chemotherapy upfront is debatable and leverages further studies in light of the upcoming triplet combinations in mHSPC, that presumably will render D-ADT obsolete in future. [Table: see text]