Adjuvant pelvic radiation is associated with improved survival and decreased disease recurrence in pelvic node-positive penile cancer after lymph node dissection: A multi-institutional study.

PURPOSE: Few studies have examined the role of radiation therapy in advanced penile squamous cell carcinoma. We sought to evaluate the association of adjuvant pelvic radiation with survival and recurrence for patients with penile cancer and positive pelvic lymph nodes (PLNs) after lymph node dissection.
MATERIALS AND METHODS: Data were collected retrospectively across 4 international centers of patients with penile squamous cell carcinoma undergoing lymph node dissections from 1980 to 2013. Further, 92 patients with available adjuvant pelvic radiation status and positive PLNs were analyzed. Disease-specific survival (DSS) and recurrence were analyzed using the Kaplan-Meier method and multivariable Cox proportional hazards model.
RESULTS: 43% (n = 40) of patients received adjuvant pelvic radiation after a positive PLN dissection. Median follow-up was 9.3 months (interquartile range: 5.2-19.8). Patients receiving adjuvant pelvic radiation had a median DSS of 14.4 months vs. 8 months in the nonradiation group, respectively (P = 0.023). Patients without adjuvant pelvic radiation were associated with worse overall survival (hazard ratio [HR] = 1.7; 95% CI: 1.01-2.92; P = 0.04) and DSS (HR = 1.9; 95% CI: 1.09-3.36; P = 0.02) on multivariable analysis. Median time to recurrence was 7.7 months vs. 5.3 months in the radiation and nonradiation arm, respectively (P = 0.042). Patients without adjuvant pelvic radiation was also independently associated with higher overall recurrence on multivariable analysis (HR = 1.8; 95% CI: 1.06-3.12; P = 0.03).
CONCLUSIONS: Adjuvant pelvic radiation is associated with improved survival and decreased recurrence in this population of patients with penile cancer with positive PLNs.