The prognostic implication of intraductal carcinoma of the prostate in metastatic castration-resistant prostate cancer and its potential predictive value in those treated with docetaxel or abiraterone as first-line therapy

Intraductal carcinoma of the prostate (IDC-P) is recognized as a newly pathological entity in 2016 WHO classification. It's role in metastatic castration-resistant prostate cancer (CRPC) remains obscure. We aimed to explore the association of IDC-P with clinical outcome and to further identify its potential predictive role in making first-line treatment decisions for mCRPC. We retrospectively analyzed data of 131 mCRPC patients. IDC-P was diagnosed by re-biopsy at the time of mCRPC. Among total patients, 45 and 41 received abiraterone or docetaxel as first-line therapies, respectively. PSA response, PSA progression-free survival (PSA-PFS) and overall survival (OS) from mCRPC to death were analyzed using Kaplan-Meier curves, Log-rank test, Cox regression models and Harrell's C-index. The incidence of IDC-P in mCRPC reached 47.3%. IDC-P was not only related to rapid PSA progression, but also associated with a 20-month decrease in OS. Among IDC-P(-) patients, PSA response, PSA-PFS and OS were comparable in abiraterone-treated and docetaxel-treated groups. In contrast, among IDC-P(+) patients, PSA response rate is higher in abiraterone-treated group vs. docetaxel-treated group (52.4% vs. 21.7%; p = 0.035). Also, PSA-PFS and OS were much longer in the IDC-P(+) abiraterone-treated group vs. the docetaxel-treated group (PSA-PFS: 13.5 vs.6.0 months, p = 0.012; OS: not reach vs.14.7 months, p = 0.128). Overall, IDC-P in mCRPC from re-biopsy was an independent prognosticator for clinical outcome. Abiraterone was observed having a better therapeutic efficacy than docetaxel as the first-line therapy in IDC-P(+) mCRPC patients. Thus, we suggest IDC-P should be considered as a novel predictive marker helping physicians making treatment decisions for mCRPC.

Oncotarget. 2017 Jul 24*** epublish ***

Jinge Zhao, Pengfei Shen, Guangxi Sun, Ni Chen, Jiandong Liu, Xin Tang, Rui Huang, Diming Cai, Jing Gong, Xingming Zhang, Zhibin Chen, Xiang Li, Qiang Wei, Peng Zhang, Zhenhua Liu, Jiyan Liu, Hao Zeng

Department of Urology, Institute of Urology, West China Hospital, Sichuan University, Chengdu, 610041, China., Department of Pathology, West China Hospital, Sichuan University, Chengdu, 610041, China., Department of Oncology, West China Hospital, Sichuan University, Chengdu, 610041, China., Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China., Department of Ultrasound, West China Hospital, Sichuan University, Chengdu, 610041, China.