Adding radiotherapy based on chemotherapy can improve cancer-specific survival in N3 penile cancer: a SEER-based study

Background Controversial effectiveness of chemotherapy and still poor prognosis prompt us to find better treatment options. This study targeted at investigating whether adding radiotherapy based on chemotherapy can effectively improve the prognosis of patients, especially for advanced penile cancer. Methods Data were obtained from the Surveillance, Epidemiology, and End Results database (SEER*Stat software V.8.3.5; USA; Accession numbers: 13693-Nov2015 and lh8N79l2), and the survival curves were conducted using the Kaplan-Meier method. Univariate and multivariate cox regression models were performed in order to determine the hazard ratios (HRs) with 95% confidence intervals (CIs) for penile cancer-specific survival (PCSS). Subgroup analysis via multivariate Cox models were conducted to discovery the different effect in population with different features. Results The median follow-up time was 25 months, the 2-year PCSS was 52.98% in the chemoradiotherapy group and 55.81% in the chemotherapy group. In multivariate analysis of all patients, combined chemoradiotherapy was not associated with PCSS (HR =0.90, 95% CI: 0.63-1.29, P=0.572). In subgroup analysis, chemoradiotherapy improved the PCSS in N3 patients compared to these patients without therapy of radiotherapy (HR =0.54, 95% CI: 0.30-0.98, P=0.043). Conclusions Our study demonstrated a significant correlation of chemoradiotherapy with improved cancer-specific survival of penile cancer (PeCa) in N3 patients. Prospective international multicenter studies are necessary in order to improve prognosis for patients with advanced penile cancer.