Background: Subglottic squamous cell carcinoma is a rare subsite of laryngeal cancer, which is believed to behave more aggressively and portend a worse prognosis than other laryngeal cancer subsites (supraglottis and glottis). Our objective was to utilize a population-based cancer registry to report the overall survival and laryngectomy-free survival in patients diagnosed with subglottic squamous cell carcinoma, and to examine trends in outcomes over time. We also compared overall survival in patients treated with primary laryngectomy versus radiation.
Methods: We carried out a retrospective population-based study of patients with a new diagnosis of squamous cell carcinoma in the province of Ontario, Canada over a 15-year period (1995-2009). We identified patients with a new diagnosis of subglottic squamous cell carcinoma using the Ontario Cancer Registry. We determined demographics, comorbidity measures, staging, survival and primary treatment with laryngectomy using the linked population-based healthcare databases in Ontario. We first determined the overall survival and laryngectomy free survival of patients with subglottic cancer. In a secular trends study, we then examined the trends in overall survival and laryngectomy-free survival over the study period.
Results: A total of 4927 cases of laryngeal carcinoma were identified, with 89 patients defined as primary subglottic carcinoma (1.8%). Among the subglottic cohort, 68 (76.4%) were male, and the mean (25th, 75th percentile) age at diagnosis was 68 (60- 77 years). The 5-year overall survival was 47.2%, while the 5-year laryngectomy-free survival was 31.5%. No differences were observed in overall survival (OS) or laryngectomy-free survival (LFS) across years over the 15-year study period (p=0.42 OS, p=0.83 LFS). Thirteen patients (15%) were treated with primary laryngectomy. Primary treatment with laryngectomy was not associated with a different risk of mortality compared with radiation.
Conclusions: The overall survival and laryngectomy-free survival of patients with subglottic carcinoma is poor and has remained stable over time (1995-2009). Primary treatment with laryngectomy does not appear to improve overall survival compared with primary radiation
