Risk Model for Lymph Node-Positive Prostate Cancer After Radical Prostatectomy.

Background: Post-radical prostatectomy (RP) lymph node positivity (pN1) is associated with disease progression. However, the optimal treatment strategy for pN1 patients has remained unclear. This study aimed to establish a risk model for predicting survival outcomes in these patients.

Methods: We retrospectively studied 528 eligible patients with pN1 undergoing RP with pelvic lymph node dissection between 2006 and 2019 at 33 participant institutions in the Japanese Urologic Oncology Study Group. Metastasis-free survival (MFS) was used to evaluate for survival outcome. A least absolute shrinkage and selection operator (LASSO)-penalized, multivariate Cox regression model for MFS was used to evaluate patients for their risk factors and establish a risk model with an associated nomogram.

Results: Grade group (GGs 4-5 vs. GGs 1-3: HR, 7.35; 95% confidence intervals (CI), 1.76-30.7; p = 0.006), pathological T-stage (pT3b or more vs. pT2 to pT3a: HR, 2.01; 95% CI, 0.93-4.34; p = 0.075), number of positive lymph nodes (HR, 2.03; 95% CI, 0.83-4.96; p = 0.044), and positive lymph node diameter (> 2 mm vs. ≤ 2 mm: HR, 2.03; 95% CI, 1.09-9.00; p = 0.034) were identified as independent prognostic factors for predicting 60-month MFS.

Conclusions: This study explored prognostic factors for pN1 prostate cancer patients for predicting their MFS and identified a risk model involving a nomogram. Randomized controlled trials are necessary in patients with pN1 prostate cancer to elucidate optimal postoperative treatment indications and selection.