Efficacy of docetaxel in castration-resistant prostate cancer patients with intraductal carcinoma of the prostate.

BACKGROUND: This study aimed to investigate the efficacy of docetaxel in castration-resistant prostate cancer (CRPC) patients with intraductal carcinoma of the prostate (IDC-P). PATIENTS AND METHODS: We retrospectively identified 79 CRPC patients with distant metastasis at initial diagnosis from June 2002 to January 2014. All patients received initial androgen deprivation therapy and 46 received docetaxel chemotherapy after progressing to CRPC. The primary outcome of interest was cancer-specific survival (CSS) from the time of CRPC diagnosis. The Cox regression model was used to confirm whether IDC-P and docetaxel would act as independent factors for prognosis. RESULTS: IDC-P was found in 62 of 79 patients. The median CSS in the IDC-P-present group was 18.2 versus 45.6 months in the IDC-P-absent group (HR 2.67; 95% CI 1.18 to 6.06; P = 0.019). Docetaxel was administered to 36 patients with IDC-P and 10 patients without IDC-P, with a median CSS of 20.5 versus 53.2 months, respectively (HR 2.98; 95% CI 1.02 to 8.64; P = 0.044). Multivariate analysis demonstrated that the presence of IDC-P and docetaxel were independent prognostic factors for CSS (P = 0.026 and 0.005, respectively) and overall survival (OS) (P = 0.029 and 0.001, respectively). CONCLUSION: The presence of IDC-P is an independent prognostic factor in CRPC patients with distant metastases and IDC-P in needle biopsies at the time of initial diagnosis. Docetaxel may prolong CSS and OS in CRPC patients with distant metastases and IDC-P in needle biopsies at the time of initial diagnosis.