Effect of postoperative radiotherapy on survival for surgically managed pT3N0 and pT4aN0 laryngeal cancer: Analysis of the National Cancer Data Base

BACKGROUND: The current study was conducted to determine the effect of postoperative radiotherapy (PORT) on overall survival in patients with surgically managed pT3-T4aN0 laryngeal squamous cell carcinoma (SCC). METHODS: A review of the National Cancer Data Base from 2004 through 2013 was performed. Patients with surgically managed pT3-4aN0 laryngeal SCC with negative surgical margins were included. Univariable and multivariable Cox regression analyses were used to determine factors associated with survival. RESULTS: A total of 1460 patients were included, 46.2% of whom had pT3N0 disease (674 patients) and 53.8% of whom had pT4aN0 disease (786 patients). Approximately 72.0% of the patients with pT3N0 disease (485 patients) and 50.1% of the patients with pT4aN0 disease (394 patients) received PORT. PORT was not found to be associated with improved overall survival on univariable analysis for patients with pT3N0 disease (hazard ratio [HR], 0.84; 95% confidence interval [95% CI], 0.62-1.14), but was for patients with pT4aN0 disease (HR, 0.57; 95% CI, 0.45-0.71). For patients with pT3N0 SCC of the larynx, in a multivariable Cox regression analysis adjusting for age >65 years, severity of comorbidities, larynx subsite, extent of laryngectomy, and number of lymph nodes removed, PORT was not found to be associated with improved survival (adjusted HR, 0.88; 95% CI, 0.64-1.21). For patients with pT4aN0 disease, the administration of PORT was associated with improved survival on multivariable analysis adjusting for age >65 years, severity of comorbidities, larynx subsite, number of lymph nodes removed, and type of hospital (adjusted HR, 0.58; 95% CI, 0.46-0.73). CONCLUSIONS: For patients with surgically managed pT3N0 laryngeal SCC with negative margins, PORT does not appear to be associated with improved survival. Despite a survival benefit, nearly 50% of patients with pT4aN0 laryngeal SCC and negative surgical margins do not receive standard-of-care PORT. Cancer 2017;123:2248–2257.