Abstract 647P
Background
Intraductal carcinoma of the prostate (IDC-P) was separated into 2 patterns: pattern 1-loose cribriform or micropapillary; pattern 2-solid or dense cribriform. While the role of different IDC-P patterns remains obscure. The purpose of this study is to explore whether two distinct IDC-P patterns respond differently to abi and doc for metastatic castration-resistant prostate cancer (mCRPC) patients. The secondary goal was to compare the therapeutic efficacy between doc and abi for patients with different IDC-P patterns.
Methods
197 mCRPC patients were enrolled in this study. IDC-P was separated into pattern 1 and pattern 2. Patients received abiraterone (abi) or docetaxel (doc) as first-line treatment. Kaplan-Meier curves and Cox regression were used for survival analyses. The primary endpoint was PSA-progression free survival (PSA-PFS) and the secondary endpoints were overall survival (OS) and PSA response.
Results
In the cohort treated with abi as the first-line therapy, patients with IDC-P pattern 2 had obviously shorter PSA-PFS than IDC-P (-) patients (P=0.026) and patients with IDC-P pattern 1 ( P=0.038). In the cohort treated with doc as the first-line therapy, IDC-P (+) patients had poorer PSA-PFS than IDC-P (-) patients (P=0.020). IDC-P pattern 2 were associated with worse PSA-PFS than IDC-P (-) (P=0.004). No significant difference in PSA-PFS and PSA response was found between abi and doc in those IDC-P (-) patients. However in those IDC-P (+) patients, abi could significantly extend PSA-PFS (P=0.001) and improved PSA response (P=0.032) compared to doc. PSA-PFS was significantly shorter in the doc group than in the abi group, both in IDC-P pattern 1 (P=0.003) and IDC-P pattern 2 patients (P=0.003).
Conclusions
This study demonstrated that two different architectural patterns of IDC-P among mCRPC patients might impact disease progression. IDC-P pattern 2 was associated with faster disease progression. Abiraterone instead of docetaxel might be more suitable in mCRPC patients with IDC-P, whether it is in IDC-P pattern 1 or IDC-P pattern 2.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Hao Zeng.
Funding
National Natural Science Foundation of China.
Disclosure
All authors have declared no conflicts of interest.