The Study on Prognosis in Patients with Adenoid Cystic Carcinoma of the External Auditory Canal

BACKGROUND: Adenoid cystic carcinoma of the external auditory canal is a rare primary malignancy, and surgery is the primary management strategy. This study aims to optimize management strategies and improve prognosis of adenoid cystic carcinoma of the external auditory canal. METHODS: Seventeen patients with adenoid cystic carcinoma of external auditory canal who had been admitted to a single institution from January 2008 to March 2019 were recruited and retrospectively reviewed. Among patients with T1 tumors, 2 underwent local external auditory canal resection, 1 received lateral temporal bone resection + superficial parotidectomy. Among patients with T2 tumors, all 5 patients underwent lateral temporal bone resection + superficial parotidectomy. Among patients with T3 tumors, 3 underwent subtotal temporal bone resection + superficial parotidectomy, 2 underwent subtotal temporal bone resection + superficial parotidectomy + radiotherapy, and 1 underwent extended temporal bone resection + superficial parotidectomy + radiotherapy. Among patients with T4 tumors, 2 underwent subtotal temporal bone resection + superficial parotidectomy and 1 underwent extended temporal bone resection + total parotidectomy + radiotherapy. RESULTS: The common manifestations included otalgia (82.4%), hearing loss (23.5%), external auditory canal mass (23.5%), otorrhea (17.6%), and aural fullness (5.9%). In the study, 5/17 (29.4%) patients had been misdiagnosed preoperatively, 5/17 (29.4%) patients revealed local recurrence, and 3/17 patients (17.6%) were identified with distant metastasis postoperatively. The 3- and 5-year overall survival rates were 88.2% and 82.3%, respectively. There was no significant difference in overall survival (P = .746) and disease-free survival (P = .933) between patients receiving different surgical approaches. Three out of 17 patients (17.6%) died of T2, T3, and T4 diseases, respectively. CONCLUSION: Otalgia is the most common manifestation of adenoid cystic carcinoma of the external auditory canal, and misdiagnosis is frequently encountered. Surgery is the preferred therapy, and local resection is associated with relapse, lateral temporal bone resection is strongly recommended in patients with early-stage tumor. Regular follow-up should be routinely conducted postoperatively to early identify local recurrence.