Minor salivary gland tumors of the palate: clinical and pathologic correlates of outcome.

Abstract

Minor salivary gland tumors of the palate are rare and may pose a diagnostic and therapeutic dilemma for the head and neck surgeon. The authors reviewed their 46 years of experience with minor salivary gland tumors of the palate to determine the factors that influence outcome and their implications for treatment. Malignant tumors were seen in 116 patients (78%) and benign tumors were found in 33 patients (22%). Adenoid cystic carcinoma was the most common malignant tumor, occurring in 43 patients, and pleomorphic adenoma was the most common benign tumor, occurring in 30 patients. Univariate analysis on the malignant lesions showed that grade 3 tumor histology (P < .001), tumor size greater than 3 cm (P < .001), perineural invasion (P = .031), bone invasion (P = .012), positive surgical margins (P < .001), and positive initial but negative final margins (P = .004) were all associated with decreased survival. With multivariate analysis, tumor size, margin status, and grade were shown to be independently associated with decreased survival (P < .05). The recurrence rate at the primary site was significantly higher for adenoid cystic carcinoma than for other histologies (P = .0059). The 2-, 5-, and 10-year disease-specific survival rates for patients with malignant disease were 96%, 87%, and 80%, respectively. Wide surgical excision with adequate margins is essential for a favorable outcome in patients with malignant minor salivary gland tumors. Postoperative radiotherapy is reserved for patients with grade 3 tumor histology, large primary lesions, perineural invasion, bone invasion, cervical lymph node metastasis, and positive margins, although a clear-cut survival advantage has not been proven. Recurrence, especially regional and distant metastasis, portends an extremely poor prognosis.