Survival Outcomes of Early Stage SCC of the Subglottis Treated with Surgery or Radiation

Abstract

Subglottic squamous cell carcinoma (SCC) is a rare malignancy representing <5% of all laryngeal cancers. Due to the rarity of this diagnosis, prospective data regarding to optimal therapy are lacking. Most patients are treated with either organ-preservation surgery or definitive radiation. This study aims to compare the outcomes for early stage subglottic SCC across treatment types. The US National Cancer Data Base (NCDB) database was queried for cases of subglottic SCC from 2004-2014. Resulting data were analyzed, including patient demographics, therapeutic modalities, and survival outcomes. Kaplan-Meier statistics and Cox proportional hazards regression analysis were used to compare survival by treatment modalities: surgery, radiation (RT) or no treatment. Propensity score-matched analysis balancing for important confounding covariates was conducted to compare survival between surgery and RT, and predictors for OS on the matched model were identified using Cox proportional hazards regression analysis. 113751 cases of laryngeal cancer were identified from NCDB database from 2004-2014. Subglottic cancer comprises of 1.8% of all laryngeal cancers in the NCDB. 249 cases of T1-2 subglottic primary, N0M0 with either definitive RT, surgery or no treatment were selected and analyzed. Median follow-up was 3.1 years (range, 0.01-12.3 years). Median age was 69 (range, 27-90 years). Overall 10-year overall survival rate was 31%. When stratified by treatment modality, 10-year overall survival was 23%, 29% and 47% for no treatment, RT and surgery, respectively (log-rank, p=0.02). In subsequent matched analysis (n=56), surgery was a predictor for improved OS (HR= 0.011, 95% CI [0.00038, 0.29], p-value=0.007). Age was a predictor for worse OS (HR 1.34, 95% CI [1.04-1.72], p=0.026), while HPV positivity was not significant (HR 0.001, p=1). Patients with early stage subglottic cancer have superior survival with surgery over radiation. Older age correlates with a worse OS while HPV status does not affect the survival outcomes. However, results should be interpreted with caution given the small sample size of the study.