Nomogram-based prediction of overall survival after regional lymph node dissection and the role of perioperative chemotherapy in penile squamous cell carcinoma: A retrospective multicenter study

Abstract

ObjectivesTo improve the prognostic allocation of patients with penile squamous-cell carcinoma (PSCC) receiving regional lymph node dissection (LND). Patients and methodsAn international, multicenter, retrospective study was performed on patients with PSCC who received regional LND, with or without perioperative therapy, from 1980 to 2017. We first used a random forest (RF) method with missing data imputation. Additionally, data were modeled using Cox proportional hazard regression, and a Cox model was also fit including prespecified variables. Based on the latter model, a nomogram for estimating 12-month and 24-month overall survival (OS) was developed. ResultsThere were 743 patients who received LND at 7 referral centers from Europe, the USA, Brazil, and China. Of these patients, 689 were analyzed: 86 (12.5%) received neoadjuvant chemotherapy (NAC); 171 (24.8%) received adjuvant chemotherapy (AC), and 74 (10.7%) received adjuvant radiotherapy.The variables significantly associated with OS were age (P < 0.001), the pathologically involved/total removed LN ratio (P < 0.001), pN stage (overall P < 0.001), and NAC (P = 0.013). NAC and AC were ineffective in N1-2 patients (clinical and pathological, respectively), whereas they provided OS improvements in N3 patients. Finally, we developed a nomogram predicting 12- and 24-month OS based on prespecified variables (c-index: 0.75). The study is limited by its retrospective nature. ConclusionsWe propose a tool that can be offered as an aid to physicians to enhance decision-making, clinical research, and patient counseling whenever LND is needed for PSCC. Administration of NAC and AC should be restricted to clinical and pathological N3 patients, respectively.