Effect of Core Needle Biopsy Number on Intraductal Carcinoma of the Prostate (IDC-P) Diagnosis in Patients with Metastatic Hormone-Sensitive Prostate Cancer.

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). 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. 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). 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.