A novel predictive model for pelvic lymph node metastasis in patients with penile cancer: A multi-institutional study.

Purpose: We determined whether a clinicopathological nomogram is able to predict the risk of pelvic lymph node metastasis (LNM) in penile cancer patients after inguinal lymph node dissection (ILND).

Methods: Ninety-eight patients with bilateral ILND who underwent pelvic lymphadenectomy at 10 centers were retrospectively analyzed. The most predictive features in the nomogram were selected by the stepwise logistic regression method and then tested and verified by multivariate logistic regression analyses. The nomogram was assessed using concordance indices and calibration curves.

Results: Of the 181 pelvic basins, pelvic LNM was observed in 52 packages (43 patients). Bilateral pelvic LNM was present in 9 patients (9/43, 20.9%). There was no crossover metastatic spread from one inguinal side to the other pelvic side. Age, previous resection, the biopsy procedure for inguinal lymph nodes, vascular invasion, and ipsilateral inguinal lymph node status were all independent risk factors for pelvic LNM (all P < 0.05) in the multivariate logistic regression analysis. The nomogram exhibited a good probability for survival agreement, with a concordance index of 0.868 (95% CI: 0.813-0.922).

Conclusions: A novel nomogram suggests that the risk of pelvic LNM can be effectively predicted in penile carcinoma patients and may provide a useful guide for clinicians. Further external validation is needed.