Intraductal carcinoma of the prostate does not independently predict adverse outcomes after radical prostatectomy: A...

Intraductal carcinoma of the prostate (IDC-P) is associated with adverse features, yet whether it independently predicts poor outcomes or merely co-segregates with high-grade disease remains unresolved. We evaluated IDC-P's independent prognostic contribution to adverse pathology after radical prostatectomy (RP).

We utilized the National Cancer Database (NCDB) to evaluate patients with cT1-4N0M0 prostate cancer (CaP) that underwent RP (n = 551,304 adenocarcinoma; n = 1,353 IDC-P). Temporal trends in IDC-P incidence were assessed by logistic regression. A restricted analytic cohort (n = 98 IDC-P, n = 14,628 adenocarcinoma) with complete Gleason Grade Group and prostate-specific antigen (PSA) data was used for multivariable logistic regression evaluating predictors of adverse pathology (≥pT3, ≥pN1, or positive surgical margins). Model discrimination was compared using C-statistics and likelihood ratio testing. Unadjusted overall survival (OS) was performed by an exploratory Kaplan-Meier analysis.

IDC-P incidence increased 6% annually (OR 1.060; P < 0.001). IDC-P patients more frequently harbored Gleason Grade Group 4 to 5 disease (66.4% vs. 26.5%), ≥pT3 pathology (75.5% vs. 55.3%), and positive surgical margins (44.9% vs. 35.4%; all P < 0.001). On multivariable analysis, IDC-P histology did not independently predict adverse pathology (aOR 1.066; P = 0.801). Adding IDC-P did not improve model discrimination (C-statistic 0.705 vs. 0.705; likelihood ratio P = 0.800). IDC-P patients had worse unadjusted median OS (183.0 vs. 197.6 months; P < 0.001).

IDC-P is rising in incidence and strongly associated with high-grade, advanced-stage disease, but does not independently predict adverse pathologic outcomes at RP after adjustment for Gleason Grade Group, clinical stage, and PSA. These findings suggest IDC-P may function primarily as a as a surrogate marker of aggressive disease biology.