Adenoid cystic carcinoma of head and neck: clinical predictors of outcome from a Canadian centre

Objectives Adenoid cystic carcinoma (ACC) is often treated with surgery, with or without adjuvant radiation therapy (RT). We evaluated disease characteristics, treatments, and potentially prognostic variables in patients with ACC. Methods Our retrospective analysis considered consecutive cases of ACC presenting at a tertiary care hospital between 2000 and 2014. Factors predictive of overall survival (os) and disease-free survival (DFS) were identified by univariate analysis. Results The 60 patients analyzed had a mean age of 58 years (range: 22-88 years), with a 2:1 female: male ratio. Tumour locations included the major salivary glands (40% parotid, 17% submandibular and sublingual), the oro-nasopharyngeal cavity (27%), and other locations (16%). Of the 60 patients, 35 (58%) received surgery with adjuvant RT; 12 (20%), RT only; 13 (22%), surgery only. Of 18 patients (30%) who experienced a recurrence within 5 years, 3 (5%) developed local recurrence only, and the remaining 15 (25%), distant metastasis. The 5-year os and DFS were 64.5% [95% confidence interval (CI): 45.9% to 78.1%] and 46.2% (95% CI: 29.7% to 61.2%) respectively. In patients without recurrence, 5-year os was 77% (95% CI: 52.8% to 89.9%), and in patients with recurrence, it was 42.7% (95% CI: 15.8% to 67.6%). Patients treated with RT only had a 5-year os of 9.2%. Predictors of 5-year DFS were TNM stage, T stage, nodal status, treatment received, and margin status; age, nodal status, treatment received, and margin status predicted 5-year os. Conclusions Despite surgery and RT, one third of patients with ACC experience distant recurrence. Patients whose tumours are not amenable to surgery have a poor prognosis, indicating a need for alternative approaches to improve outcomes.