Risk factors for survival and distant metastasis in 125 patients with head and neck adenoid cystic carcinoma undergoing primary surgery

Purpose Adenoid cystic carcinoma (AdCC) is generally slow growing but has highly metastatic potential to distant organs. Several factors and biomarkers are associated with metastasis and treatment outcomes, although further definition is needed. Therefore, this study aimed to evaluate the risk factors for survival and distant metastasis in patients with head and neck AdCC. Methods This study included 125 patients with previously untreated AdCC who underwent primary surgery with or without radiotherapy in our tertiary referral centre. Univariate and multivariate Cox proportional hazard regression analyses were used to identify risk factors associated with overall survival (OS), cause-specific survival (CSS), disease-free survival (DFS), and distant metastasis-free survival (DMFS). Factors associated with OS in patients with distant metastasis were separately analysed. Results During a median follow-up of 9.8 years (range 3.0-22.6 years), 58 patients (46.4%) had distant metastasis and 29 (23.2%) died of disease. Multivariate analyses showed that lymphovascular invasion, lymph node metastasis, and distant metastasis were independent factors of OS and CSS outcomes (all P < 0.05). The T classification and extranodal extension were independent factors of DFS and DMFS outcomes (P < 0.05). After patients presented with distant metastasis, the median survival was 5.8 years. Multivariate analyses showed that extranodal extension and regional recurrence were independent factors of survival after occurrence of distant metastasis (P < 0.05). Conclusion Several clinicopathological factors can predict distant metastasis and survival of patients with AdCC treated with primary surgery. This may promote post-treatment surveillance in patients with AdCC.