Effect of core needle biopsy number on intraductal carcinoma of the prostate (IDC-P) diagnosis in patients with metastatic hormone-sensitive prostate cancer.

BACKGROUND The number of core needle biopsies in metastatic prostate cancer cases are sometimes reduced to avoid various complications. We analyzed whether core needle biopsy number influence IDC-P detection rate in patients with metastatic castration-sensitive prostate cancer (mHSPC). METHODS We retrospectively evaluated data from 150 patients diagnosed with mHSPC. Subjects were allocated to three groups according to the number of core biopsies performed: ≤ 5, 6-9, and ≥ 10. The study endpoints were the cancer-specific survival (CSS) and overall survival (OS) rates. RESULTS For patients who underwent ≥ 10 core biopsies, a significant difference on CSS was detected between with or without IDC-P (P = 0.016). On the other hand, the difference decreased as the number of core biopsies became smaller (6-9; P = 0.322 and ≤ 5; P = 0.815). A similar trend was identified for the OS outcome. A significant difference on OS was also found between with or without IDC-P in patients who underwent ≥ 10 and 6-9 core needle biopsies (P = 0.0002 and 0.017, respectively), but not in those who underwent ≤ 5 core biopsies (P = 0.341). IDC-P served as a stronger prognostic marker for CSS and OS than did the other factors included in the multivariate analysis for patients had ≥ 10 core biopsies (P = 0.016, and P = 0.0014, respectively). CONCLUSIONS Given the IDC-P detection and its value as a prognostic marker, we propose the performance of ≥ 10 core biopsy procedures in patients diagnosed with mHSPC to minimize the sampling error of the IDC-P.