The Prognostic Impact of Intraductal Carcinoma of the Prostate: A Systematic Review and Meta-Analysis.

PURPOSE: This systematic review and meta-analysis aimed to assess the prognostic impact of intraductal carcinoma of the prostate (IDC-P) in patients with prostate cancer (PCa). MATERIAL AND METHODS: A systematic search was performed according to the Preferred Reporting Items for Systemic Review and Meta-analysis statement. We searched PubMed, Web of Science, Cochrane Library, and Scopus databases up to October 2019. The endpoints were biochemical recurrence-free, cancer-specific, and overall survival (BRFS, CSS, and OS, respectively). RESULTS: We identified 32 studies with 179,766 patients. Thirty-one studies comprising 179,721 patients with localized and advanced PCa were eligible for the meta-analyses. In localized PCa, IDC-P was associated with adverse outcomes including lower BRFS (pooled hazard ratio [HR] 2.09, 95% confidence interval [CI] 1.75-2.50) and CSS (pooled HR 2.93, 95% CI 2.25-3.81). In advanced PCa, patients with IDC-P had lower OS than those without IDC-P (pooled HR 1.75, 95% CI 1.43-2.14). Subgroup analysis by specimen type revealed that IDC-P is a significant negative prognostic factor in both biopsies and prostatectomy specimens. Moreover, subgroup analyses based on the histopathological IDC-P definitions revealed that IDC-P was significantly associated with lower BRFS, CSS, and OS for almost all definitions. CONCLUSIONS: ICD-P is a histopathological feature of biologically and clinically aggressive PCa. It confers worse oncological outcomes in both localized and advanced PCa, whether assessed in biopsy or prostatectomy specimen. Pathologist should assess for and report on the presence of ICD-P in all prostate specimens. Urologist and radiation oncologist should consider this adverse feature in their clinical decision making.