Predictors of Postoperative Radiation Following Laser Resection in Early-Stage Glottic Cancer

Abstract

Objective Guideline recommendations for the treatment of early-stage glottic cancer are limited to single-modality therapy with surgery or radiation alone. We sought to investigate the clinicopathologic and treatment factors associated with the use of postoperative radiation therapy (PORT) following laser excision for patients with T1-T2N0 glottic squamous cell carcinoma (SCC). Study Design Retrospective observational study of the National Cancer Database. Setting National Cancer Database review from 2004 to 2014. Patients and Methods A total of 1338 patients with primary cT1-T2N0M0 glottic SCC undergoing primary laser excision were included. Hospitals were divided into quartiles based on yearly volume of laryngeal laser cases performed. Multivariate logistic regression was performed to identify independent predictors of PORT. Results The overall rate of PORT was 30.0%. Predictors of PORT included treatment at lower-volume hospitals (adjusted odds ratio [aOR] for quartiles 2-4, 1.32-4.84), positive margins (aOR, 3.83 [95% CI, 2.54-5.78]), and T2 tumors (aOR, 3.58 [95% CI, 2.24-5.74]). PORT utilization demonstrated a strong inverse correlation with hospital volume. Among top-quartile hospitals, the rate of PORT was 11.2%, while rates of PORT at second-, third-, and fourth-quartile institutions were 19.2%, 32.2%, and 37.4%, respectively. Conclusions Predictors of PORT in multivariable analysis included treatment at lower-volume facilities, positive margins, and T2 disease. This study highlights the importance of treating early-stage glottic carcinoma at high-volume institutions. In addition, there is a need to reevaluate the use of PORT and reduce the rate of dual-modality therapy for patients with early-stage glottic SCC.