Pathologic Distribution and Survival Outcomes of 137 External Auditory Canal Cancers

Background and Objectives External auditory canal (EAC) cancer is a rare malignancy with limited data in Korea.This study aimed to analyze the pathological distribution and survival outcomes of EAC cancer by comparing squamous cell carcinoma (SCCa) and adenoid cystic carcinoma (ACCa). Subjects and MethodWe retrospectively reviewed 137 patients with primary EAC cancer who were treated at a single tertiary center between 2015 and 2026.Tumors were staged using the Pittsburgh system for SCCa and a specific updated system for ACCa.Survival data were supplemented with queries from the National Health Insurance database. ResultsThe cohort (mean age 65.6 years) predominantly presented with SCCa (73.0%), followed by ACCa (20.4%).Right-sided involvement was more frequent in both groups (62.8%).Patients with ACCa were significantly younger (55.5 years) than those with SCCa (67.7 years, p<0.001).The 5-year overall survival (OS) rate of the entire cohort was 78.9%.ACCa demonstrated a significantly better 5-year OS rate (100%) than those with SCCa (72.4%, p=0.011).For SCCa, the clinical stage was a significant prognostic factor, with 5-year OS rates of 97.2% for Stage I and 44.1% for Stage IV (p=0.003).Conclusion SCCa is the most common histologic subtype of EAC cancer in Korea, followed by ACCa.ACCa usually occurs at a younger age and has a better prognosis than SCCa.Both subtypes showed a notable right-sided predominance, potentially linked to regional behavioral factors.