Clinical characteristics and prognostic factors of adenoid cystic carcinoma of the head and neck.

OBJECTIVES/HYPOTHESIS This study was intended to evaluate prognostic factors and the role of postoperative radiotherapy (RT) in patients with adenoid cystic carcinoma (ACC) of the head and neck (ACCHN). STUDY DESIGN Retrospective study. METHODS Eighty-eight patients with ACCHN who underwent curative intent surgery with or without RT between 1991 and 2009 at a single institute were retrospectively analyzed. RESULTS Patients with ACC of the sinonasal area (P=.005) and those with diabetes mellitus (DM; P=.027) showed a significantly higher risk of local recurrence. Age (<40 or >60 years, P=.028) and tumor stage III or IV (P=.022) were significant adverse factors predicting distant metastasis. High-grade histology (P=.014) and DM (P=.027) were independently associated with shorter disease-free survival (DFS). In addition, postoperative RT (≥59 Gy) significantly enhanced local control (P=.025) and DFS (P=.001) in both univariate and multivariate analyses. CONCLUSIONS Age, DM, tumor site, histologic grade, and stage were independently significant prognostic factors for ACCHN. In addition, an adequate dose of postoperative radiotherapy can improve local control and DFS of patients with ACCHN.