Adjuvant radiation compares favorably to chemotherapy in patients with carcinoma penis and nodal positivity restricted to groin

Abstract

Objectives: To compare overall survival (OS) between adjuvant radiation, chemotherapy and chemoradiation (CCRT) postsurgery for node-positive patients with carcinoma penis.

Methods: Prospectively maintained registry for 45 patients receiving adjuvant treatment following lymph node dissection from 2011 to 2017, having minimum 6 months follow-up and more than 2 positive inguinal nodes was analyzed. Patients without pelvic nodal positivity (n= 32) were treated by radiotherapy (RT) (n = 25) or chemotherapy (n = 7); CCRT (n = 6) or chemotherapy (n = 7) was used in patients with positive pelvic nodes (n = 13). Data was collected for age, comorbidities, body mass index, tobacco exposure, treatment modality, tumor grade, pathological T and N stage, and extra-nodal extension. OS was compared between different treatment modalities stratifying patients with and without pelvic nodal positivity. Multivariate cox proportional hazard analysis was used to narrow down remaining variables and Inverse Probability Treatment Weights modeling was used to determine average treatment effect.

Results: About 12 of 14 patients in the chemotherapy group received both cisplatin and paclitaxel. Pathological T stage, N stage and extra-nodal extension had significant association with OS on multivariate analysis. Among patients with nodal positivity restricted to groin the estimated average OS when all patients received adjuvant RT was 1,438 days (95% confidence interval [CI] 1,256-1,619 days, Pvalue <0.0001). The estimated average OS if all patients received chemotherapy was lower by 1,007 days (95% CI 810-1,202 days, P value <0.0001). Among patients with positive pelvic nodes the estimated average OS when all patients received adjuvant CCRT was 467 days (95% CI 368-566 days, P value <0.0001). The estimated average OS difference if all patients received chemotherapy was 17 days (95% CI -144 to 178 days, Pvalue 0.21).

Conclusion: In patients with nodal positivity limited to groin, adjuvant RT proved superior to chemotherapy. Among patients with pelvic nodal positivity, CCRT offers no significant OS advantage over combination chemotherapy.

Keywords: Chemotherapy; Penile neoplasms; Radical ilioinguinal lymphadenectomy; Radiotherapy; Survival.