The aim of the current study was to test whether the grade group assessed in the index tumor nodule predicts biochemical recurrence after surgery. The study cohort series included 144 consecutive patients treated by laparoscopic radical prostatectomy. The following parameters were evaluated in each case: type of radical prostatectomy (with/without lymphadenectomy), pT and pN status, histologic type of prostate carcinoma (acinar versus mixed histology), surgical margin resection status, perineural invasion, lymphovascular invasion, biochemical recurrence status, presence of tertiary Gleason 5 pattern, and grade group that was assessed both in overall prostate cancer and in index (dominant) tumor nodule. Twenty patients (13.9%) experienced postoperative biochemical recurrence at a mean follow-up time of 12.2 months. The univariate survival analysis selected type of radical prostatectomy, histological subtype, lymphovascular invasion, American Joint Committee on Cancer pT and pN classification, tertiary Gleason 5 pattern, preoperative serum prostate specific antigen level, and the grade group assessed in both the overall prostate and index tumor nodule as significant for biochemical recurrence-free survival. Type of radical prostatectomy (P = .020), histological subtype (P = .002), lymphovascular invasion (P = .023), tertiary Gleason pattern 5 (P = .016), and grade group classification in index tumor nodule (P ≤ .0001) were selected as independent predictors of biochemical recurrence-free survival. In conclusion, our results validate grade group in the index tumor nodule as an independent predictor of biochemical recurrence-free survival, thus emphasizing the value of reporting grade group in index tumor nodule. The main limitation of our study is the relatively low number of cases in the current series, suggesting the need of large confirmatory studies.
