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

Objective: This study aimed to investigate the prognostic factors and treatment outcomes in patients with the external auditory canal (EAC) squamous cell carcinoma (SCC).

Methods: 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).

Results: 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).

Conclusion: 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.

Level Of Evidence: 4 Laryngoscope, 133:2203-2210, 2023.