Oncological outcomes of pathologically organ-confined, lymph node-positive prostate cancer after radical prostatectomy

BACKGROUND: The aim of this study was to investigate the impact of lymph-node involvement on oncological outcomes in patients with pathologically organ-confined prostate cancer (pT2 CaP) after radical prostatectomy (RP).

METHODS: We retrospectively analyzed 9,631 pT2 CaP patients who underwent RP at a single institution between 1998 and 2018. Kaplan-Meier plots and Cox regression models (CRMs) assessed biochemical recurrence (BCR)-free survival and metastasis-free survival (MFS) according to N-stage. In subgroup analyses of N1 patients, Kaplan-Meier plots and CRMs were stratified according to adjuvant treatment.

RESULTS: Of 9,631 pT2 staged patients, 241 (2.5%) harbored lymph-node metastases after RP (pN1). The median follow-up was 60.8 months. No pT2 N1-staged patient died due to CaP. The 5-year BCR-free survival rates were 54.7 vs. 88.4% in pT2 N1 vs. pT2 N0 patients, respectively (P < 0.001). The 5-year MFS rates were 92.5 vs. 98.9% in pT2 N1 vs. pT2 N0 patients, respectively (P < 0.001). Within pT2 N1 patients, presence of ≥3 positive lymph nodes was an independent risk factor for BCR (hazard ratio [HR] 3.4, P < 0.001) and for metastatic progression (HR 1.7, P = 0.04). Finally, 3-year BCR-free survival was improved in pT2 N1 patients treated with adjuvant radiation therapy (87.1% vs. 63.7% for patients who received other treatment options [P < 0.001]).

CONCLUSION: Patients with pathologically organ-confined but lymph node-positive CaP exhibited favorable oncological outcomes after RP. Presence of ≥3 positive LNs predicted higher rates of BCR and metastatic progression. In consequence, in pT2 N1 patients treated with RP with ≥3 positive LNs, adjuvant treatment may be considered.9.