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.