Analysis of Prognostic Factors For External Auditory Canal Carcinoma: A 22-Year Experience.

Abstract

This study aimed to investigate the prognostic factors and treatment outcomes in patients with the external auditory canal (EAC) squamous cell carcinoma (SCC). All patients diagnosed with EAC SCC and treated with curative intent at a single tertiary institution were retrospectively reviewed over a 22-year period. Treatment modalities included surgery with adjuvant treatment or definitive radiotherapy. The primary endpoints were overall survival (OS) and disease-specific survival (DSS). There were 51 patients in our cohort. The 5-year OS and DSS were 64.0% ± 7.0% and 72.0% ± 7.0% respectively. Patients in the surgical arm and RT arm showed no significant difference in OS, DSS, and LRFS (p=0.075, 0.062, 0.058 respectively). Compared to other routes of spread within the temporal bone, pattern of posterior disease invasion (involving mastoid/sigmoid sinus) showed poorer OS and DSS on multivariate analysis (hazard ratio, HR4.34 and 5.88; p= 0.006 and 0.009). On multivariate analysis, the following factors were independently prognostic of poorer OS and DSS: Previous radiotherapy (HR 3.29 and 4.81, p= 0.021 and p= 0.029); Presence of facial nerve palsy (HR 3.80 and 7.63, p= 0.013 and p= 0.003); Posterior pattern of invasion (HR4.05 and 3.59, p= 0.013 and p= 0.043). Advanced modified Pittsburgh stage was not predictive of poor OS and DSS (HR1.17 and 1.17 E+5, p= 0.786 and p= 0.961). Presence of previous radiotherapy, facial nerve palsy and posterior pattern of disease invasion were independent prognostic factors of poorer survival in patients with EAC SCC. 4 Laryngoscope, 133:2203-2210, 2023.