Efficacy of bi-weekly docetaxel in hormone-sensitive metastatic prostate cancer (mHSPC).

Abstract

e17070 Background: In pts with mHSPC, docetaxel in a three-week schedule is associated with better overall survival (OS) vs androgen suppression alone, principally in pts with high tumor volume(HV). In pts with mCRPC stage, biweekly docetaxel demonstrated greater efficacy and a better toxicity profile. There are few published data about the use of bi-weekly docetaxel in pts with mHSPC. Methods: Pts with mHSPC and treated with bi-weekly docetaxel from January 2014 to December 2020 at The Comprehensive Cancer Center Clinica de Occidente in Cali-Colombia, were retrospectively identified. We collected relevant variables from electronic medical records. Our primary objective was to determine the efficacy in OS and the incidence of febrile neutropenia (FN). We performed Kaplan Meier, and cox regression analysis with relevant variables. Results: 69 pts were included, with a mean follow-up time of 45 months. Median age was 72y, 82% had ECOG PS 0/1, 74% grade group 4-5, 23% visceral metastases, and 93% de novo metastatic disease. The median OS was 51 months, and 39% at 5 years. In HV and de novo metastatic pts, the median OS was 49 months. The median time to development of mCRPC was 34 months. 35% of the patients had a PSA < 0.2ng/mL at month 6. In the univariate analysis, pts with HV (HR 10.49 95% CI 1.43-76.50, P = 0.0005), PSA > 0.2ng/mL (HR 4.43 95% CI 2.09-9.41, P = 0.0000), imagen objective response rate (ORR) (HR 1.47 95% CI 1.09-1.95, P = 0.0156) and PS ECOG > 0, (HR 3.3 CI95% 1.31-8.45, P = 0.003) had worse OS. Neither histologic grade 5 (HR 1.07, P = 0.8), visceral metastases (HR 1.2, P = 0.57), or de novo metastatic disease (HR 0.84, P = 0.74) were significantly associated. In the multivariate analysis, only PSA of > 0.2ng/mL at 6 months remained significantly [Table 1]. FN was detected in 3.2% of patients. Conclusions: We report the study with the largest number of patients and follow-up time (median 42.5 months) in patients with mCSPC who used biweekly docetaxel in addition to standard androgen suppression. The outcomes are similar, indirectly compared, to those reported in the CHAARTED study in OS, specifically in the de novo high-volume metastatic subgroup (CHAARTED 48 months, current study 49 months), better time to CRPC (20 months CHAARTED, 34 months current study), and with a lower incidence of FN (6% CHAARTED, 2% current study). None of the pts used primary granulocyte colony-stimulating factor prophylaxis. The use of biweekly docetaxel in this scenario offers high efficacy with less toxicity. Randomized studies are strongly recommended to confirm these results. [Table: see text]