Survival analysis of patients with metastatic castration-resistant prostate cancer treated with docetaxel plus prednisone

Abstract

Objective To explore the potential value of patient characteristics in predicting overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel plus prednisone.Methods We retrospectively analyzed the data of 115 consecutive Chinese patients with mCRPC received docetaxel chemotherapy in our institution from Nov.2005 to Sep 2011.The median age at diagnosis was 65 years old and median serum prostate-specific antigen (PSA) level at diagnosis was 100.0 μg/L.The Gleason score≤7 in 26 patients and ≥8 in 89 patients.The median age at chemotherapy was 68 years old,ranging from 51 to 82 years old.The median baseline PSA level was 90.5 μg/L,ranging from 0.8 to 4066.4 μg/L.The median baseline hemoglobin (Hb) concentration was 121 g/L and median baseline alkaline phosphatase (ALP) concentration was 110 U/L.The time to castration resistance ranged from 2 to 114 months and the median value was 23.All 115 patients have bone metastasis,and 16 cases were simultaneously observed the presence of visceral metastasis including lung (9 cases),bladder (4 cases),liver (2 cases) and brain (1 case).The average cycles of chemotherapy was 6,ranging from 1 to 16.We retrospectively collected the variables including patient characteristics at diagnosis and characteristics before the chemotherapy.All laboratory analyses were performed in the same laboratory.Survival analysis was performed using KaplanMeier curves,and the differences in overall survival rates were assessed using the log-rank test.Only variables that were statistically significant in the univariate analysis (P＜0.05) were included in the multivariate model.Results The follow-up was performed until April 30,2012,and median follow-up time was 45 months,ranging from 2 to 74 months.During the follow-up period,87 of 115 patients (75.7％) died and the median OS for the entire cohort was 17 months,ranging from 2 to 46 months.The univariate analysis identified a total of 8 statistically significant predictors of OS:baseline serum PSA level,baseline Hb concentration,baseline ALP concentration,baseline lactate dehydrogenase (LDH) concentration,baseline gamma-glutamyl transpeptidase (GGT) concentration,ECOG PS,time to castration resistance and cycles of chemotherapy.Subsequent multivariate analysis reserved baseline ALP≥110 U/L,baseline Hb＜110 g/L,time to castration resistance＜23 months and cycles of chemotherapy＜6 as independent prognostic factors for shorter OS.Conclusions This retrospective analysis has demonstrated that baseline ALP concentration,baseline Hb concentration,time to castration resistance and cycles of chemotherapy could provide independent prognostic information of OS in Chinese patients with mCRPC treated with docetaxel plus prednisone. Key words: Castration-resistant prostate cancer; Docetaxel; Prognosis ; ALP ; Time to castration resistance