Elective neck dissection in patients with head and neck adenoid cystic carcinoma: an international collaborative study.

Background: Adenoid cystic carcinoma (ACC) accounts for 3-5 % of all head and neck malignancies. Investigations of outcomes from elective neck dissection (END) for patients with ACC are sparse. This study aimed to assess the impact of END on the survival of patients with ACC.
Methods: This retrospective multicentered study investigated 270 patients who underwent neck dissection. A multivariate analysis assessed associations of clinical and histopathologic characteristics with survival outcomes.
Results: The primary tumor sites included the oral cavity in 250 patients (55 %), the major salivary glands in 133 patients (29 %), the sinonasal mucosa in 68 patients (15 %), and the larynx in six patients (1 %). The overall rate of occult nodal metastases among the patients who underwent END was 17 % (38/226). The highest incidence of occult nodal metastases was with the oral cavity (66 %). The 5-year overall survival (72 and 79 % for patients with or without END, respectively) and disease-specific survival (74 and 81 % for patients with or without END, respectively) were similar in the two groups. The subgroup analysis of patients according to the primary site showed no significant impact of END on outcome. In the multivariate analysis, primary site, T classification, and N classification were the only variables associated with outcome.
Conclusions: The incidence of occult neck metastases among patients with ACC is 17 %. The highest incidence of occult metastases is with the oral cavity. Statistical analysis showed no survival advantage for patients who underwent END compared with those who did not.