Could the New pN Staging Classification Better Predict the Prognosis of Penile Cancer? A Population-Based Analysis

Background: The 8th edition of the American Joint Committee on Cancer (AJCC) has made new revisions to the N staging of penile cancer (PeCa). This study aimed to evaluate the prognostic value of the new N staging classification.Methods: This cohort was included from the Surveillance, Epidemiology, and End Results (SEER) database (1988-2016). Overall survival (OS) and cancer-specific survival (CSS) were evaluated using Kaplan-Meier survival curve. The Cox proportional hazards model was employed to calculate hazard ratio (HR) and 95% confidence intervals (CI).Results: Among the included 583 patients, 270 patients had only one positive inguinal lymph node (ILNP), 115 had two ILNPs, and 198 had 3 or more ILNPs. Kaplan-Meier analysis indicated that The OS and CSS of patients with ILNP = 2 were not statistically different from those with ILNP =1 (p = 0.394; p = 0.760), but had OS and CSS benefit over those with ILNP >= 3 (p = 0.017; p = 0.020). Cox proportional hazards regression analysis indicated that patients with ILNP = 2 and ILNP =1 have similar OS and CSS (HR = 0.80,p = 0.153; HR = 0.74,p = 0.148), but patients with ILNP >= 3 had worse OS and CSS than patients with ILNP = 2 (HR = 1.56, p = 0.007; HR = 1.86, p = 0.003).Conclusions: PeCa patients with only one or two lymph node metastases had similar survival outcomes. AJCC 8th edition pN staging has a better discriminative ability to predict the prognosis and can accurately stratify mortality risk in PeCa.