External auditory canal stenosis after radiation therapy.

Abstract

To determine whether the risk of external auditory canal stenosis from external-beam radiation therapy is dose dependent. Retrospective chart review. The presence of external auditory canal disease was recorded for patients who received low-dose (e.g., lymphoma [20-40 Gy]), medium-dose (e.g., chemodectoma [40-55 Gy]), or high-dose (e.g., parotid and nasopharyngeal neoplasms [55-75 Gy]) external-beam radiation therapy from 6 months to over 8 years following treatment. The incidence of external auditory canal disease was compared between groups. None of 13 low-dose, none of 19 medium-dose, and 8 of 91 (8.7%) high-dose external-beam radiation therapy subjects developed ipsilateral external auditory canal stenosis. No external auditory canal stenosis developed in patients treated with high-dose external-beam radiation therapy in the absence of parotid surgery. External auditory canal stenosis developed only in patients treated with parotidectomy and high-dose external-beam radiation therapy (P =.0059), and all of these cases of external auditory canal stenosis developed within 3 years of radiation therapy. High dose external-beam radiation therapy alone does not significantly predispose patients to external auditory canal stenosis. However, combined high-dose external-beam radiation therapy and surgery around the external auditory canal do significantly increase the risk of external auditory canal stenosis.