Differing risk of cancer death among patients with lymph node metastasis after radical prostatectomy and pelvic lymph node dissection: identification of risk categories according to number of positive nodes and Gleason score.

OBJECTIVES: To evaluate the outcomes in patients with node-positive prostate cancer (PCa) after radical prostatectomy (RP) and pelvic lymph node dissection (PLND) according to the number of positive lymph nodes (LNs). To identify different risk groups among patients with node-positive PCa.

PATIENTS AND METHODS: We evaluated 98 consecutive patients with pN1M0 PCa who underwent RP between November 1995 and May 2011. Kaplan-Meier and Cox proportional univariable and multivariable regression models were used to analyse the survival rates. Patients were divided into two groups according to number of positive LNs using the most informative positive LN theshold for predicting survival, then into three different risk groups according to number of positive LNs and pathological Gleason score (GS).

RESULTS: Mean (range) follow-up was 68.4 (10-192) months. Patients with 1-3 positive LNs (n = 75; 76.5%) had significantly better cancer-specific survival (CSS) and overall survival (OS) compared with those with >3 positive nodes (n = 23; 23.4%; P < 0.01). Patients with 1-3 positive LNs and pathological GS ≤7 (Group 1) had significantly better CSS than those with >3 positive LNs or GS 8-10 (Group 2 [P = 0.015]). Group 2 patients, moreover, had significantly better CSS (P = 0.019) and OS (P = 0.021) than those with >3 positive LNs and GS 8-10 (Group 3).

CONCLUSIONS: Patients with 1-3 positive LNs have higher CSS and OS rates than those with >3 metastatic LNs. Taking into account the pathological GS, as well as the number of positive nodes, three risk group categories with considerable differences in terms of survival can be found. Patients with LN-positive PCa should be stratified into different groups according to these two measures, to obtain a better prediction of oncological outcomes.