More extensive pelvic lymph node dissection improves survival in patients with node-positive prostate cancer

Background The role of extended pelvic lymph node dissection (ePLND) in treating prostate cancer (PCa) patients with lymph node invasion (LNI) remains controversial. Objective The relationship between the number of removed lymph nodes (RLNs) and cancer-specific mortality (CSM) was tested in patients with LNI. Design, setting, and participants We examined data of 315 pN1 PCa patients treated with radical prostatectomy (RP) and anatomically ePLND between 2000 and 2012 at one tertiary care centre. All patients received adjuvant hormonal therapy with or without adjuvant radiotherapy (aRT). Outcome measurements and statistical analysis Univariable and multivariable Cox regression analyses tested the relationship between RLN number and CSM rate, after adjusting to all available covariates. Survival estimates were based on the multivariable model; patients were stratified according to RLN number using points of maximum separation. Results and limitations The average number of RLNs was 20.8 (median: 19; interquartile range: 14-25). Mean and median follow-up were 63.1 and 54 mo, respectively. At 10-yr, the CSM-free survival rate was 74.7%, 85.9%, 92.4%, 96.0%, and 97.9% for patients with 8, 17, 26, 36, and 45 RLNs, respectively. By multivariable analyses, the number of RLNs independently predicted lower CSM rate (hazard ratio [HR]: 0.93; p = 0.02). Other predictors of CSM were Gleason score 8-10 (HR: 3.3), number of positive nodes (HR: 1.2), and aRT treatment (HR: 0.26; all p ≤ 0.006). The study is limited by its retrospective nature. Conclusions In PCa patients with LNI, the removal of a higher number of LNs during RP was associated with improvement in cancer-specific survival rate. This implies that ePLND should be considered in all patients with a significant preoperative risk of harbouring LNI. Patient summary We found that removing more lymph nodes during prostate cancer surgery can significantly improve cancer-specific survival in patients with lymph node invasion.