Pathological features of lymph node metastasis for predicting biochemical recurrence after radical prostatectomy for prostate cancer.

Purpose: Subclassification of nodal stage may have prognostic value in men with lymph node metastasis at radical prostatectomy. We explored the role of extranodal extension, size of the largest metastatic lymph node and the largest metastasis, and lymph node density as predictors of biochemical recurrence.Materials and Methods: We reviewed pathological material from 261 patients with node positive prostate cancer. We examined the predictive value when adding the additional pathology findings to a base model including extraprostatic extension, seminal vesicle invasion, radical prostatectomy Gleason score, prostate specific antigen and number of positive lymph nodes using the Cox proportional hazards regression and Harrell concordance index.Results: The median number of lymph nodes removed was 14 (IQR 9, 20) and the median number of positive lymph nodes was 1 (IQR 1, 2). At a median followup of 4.6 years (IQR 3.2, 6.0) 155 of 261 patients experienced biochemical recurrence. The mean 5-year biochemical recur...