Identifying low cancer-specific mortality risk lymph node-positive radical prostatectomy patients.

Objectives: To identify low cancer-specific mortality (CSM) risk lymph node-positive (pN1) radical prostatectomy (RP) patients.

Methods: Within Surveillance, Epidemiology and End Results database (2010-2015) pN1 RP patients were identified. Kaplan-Meier plots and multivariable Cox-regression (MCR) models were used. Pathological characteristics were used to identify patients at lowest CSM risk.

Results: Overall, 2197 pN1 RP patients were identified. Overall, 5-year cancer-specific survival (CSS) rate was 93.3%. In MCR models ISUP GG1-2 (hazard ratio [HR]: 0.12, p < 0.001), GG3 (HR: 0.14, p < 0.001), GG4 (HR: 0.35, p = 0.002), pT2 (HR: 0.27, p = 0.012), pT3a (HR: 0.28, p = 0.003), pT3b (HR: 0.39, p = 0.009), and 1-2 positive lymph nodes (HR: 0.64, p = 0.04) independently predicted lower CSM. Pathological characteristics subgroups with the most protective hazard ratios were used to identify low-risk (ISUP GG1-3 and pT2-3a and 1-2 positive lymph nodes) patients versus others (ISUP GG4-5 or pT3b-4 or ≥3 positive lymph nodes). In Kaplan-Meier analyses, 5-year CSS rates were 99.3% for low-risk (n = 480, 21.8%) versus 91.8% (p < 0.001) for others (n = 1717, 78.2%).

Conclusions: Lymph node-positive RP patients exhibit variable CSS rates. Within this heterogeneous group, those at very low risk of CSM may be identified based on pathological characteristics, namely ISUP GG1-3, pT2-3a, and 1-2 positive lymph nodes. Such stratification scheme might be of value for individual patients counseling, as well as in design of clinical trials.