Risk Factors for Locoregional Recurrence and Distant Metastasis in 143 Patients with Adenoid Cystic Carcinoma of the External Auditory Canal.

AIMS:Adenoid cystic carcinoma (ACC) grows slowly and is characterised by potential recurrence and metastasis to distant organs. This study aimed to evaluate the risk factors for locoregional recurrence (LRR) and distant metastasis in patients with ACC of the external auditory canal (EAC). MATERIALS AND METHODS:Demographic, pathological, therapeutic and survival data of 143 patients with EAC ACC were reviewed in this study. Univariate and multivariate Cox proportional hazard regression analyses were carried out to determine the risk factors for LRR and distant metastasis. Factors associated with overall survival after LRR and distant metastasis were also analysed. RESULTS:During a median follow-up of 49 months, 31 of 143 patients were observed with LRR and 34 developed distant metastasis. Bone invasion and histological subtype were independent risk factors for locoregional recurrence-free survival. T stage and LRR were independent risk factors for distant metastasis-free survival. Salvage surgery and adjuvant radiotherapy or chemoradiotherapy for LRR resulted in better survival, whereas extrapulmonary metastasis and LRR were associated with a higher risk of poor survival after distant metastasis. CONCLUSION:Patients with distant metastases, especially those with LRR, are at significant risk of poor prognosis. Our findings emphasise the importance of long-term regular follow-up and recommend surgical intervention with radiotherapy for recurrent EAC ACC.