Analysis of the clinicopathological characteristics and prognosis of adenoid cystic carcinoma of the intraoral minor salivary glands: a retrospective study of 40 cases.

The clinicopathological aspects and prognostic factors of 40 patients with adenoid cystic carcinoma (ACC) of the intraoral minor salivary glands, treated between 2007 and 2017 at a single institution, were evaluated retrospectively. Twenty-six were female and 14 were male, and they ranged in age from 26 to 81 years (median 55 years). ACC occurred mainly in the palate, with 54.8% of cases presenting T3-T4 lesions. Curative surgery was performed in all patients, and 62.5% of patients were treated with postoperative adjuvant radiotherapy. In the final analysis, positive surgical margins were noted in 57.5% of cases and perineural invasion in 70%. Follow-up was at least 13 months (range 13-141 months, median 59 months). Nineteen patients (47.5%) developed recurrent disease after initial surgery and nine patients had died at the end of follow-up. The 5- and 10-year overall survival rates were 88.3% and 25.6%, respectively. The 5- and 10-year disease-free survival rates were 75.6% and 34.0%, respectively. Patients with a tumour size >4cm and those with positive surgical margins showed a significantly higher risk of local recurrence. Elective neck dissection is suggested for patients with clinically positive lymph nodes or a locally advanced tumour, especially those undergoing microvascular reconstruction. The survival analysis results are similar to those reported previously in the literature.