MUCOEPIDERMOID CARCINOMA OF THE MAJOR SALIVARY-GLANDS - CLINICAL AND HISTOPATHOLOGIC ANALYSIS OF 234 CASES WITH EVALUATION OF GRADING CRITERIA

BACKGROUND, The authors had previously conducted an investigation of m inor salivary gland mucoepidermoid carcinoma, in which they demonstrat ed that certain clinical and histopathologic features were useful in p redicting biologic outcome. The current study investigated the usefuln ess of these features in determining the prognoses of patients with mu coepidermoid carcinomas of the major salivary glands. METHODS, Clinica l data and 15 histopathologic features were compared in 4 patient grou ps based on outcome after initial treatment. The outcome groups were 1 ) survival without disease, 2) survival with tumor recurrence only, 3) survival with metastasis, and 4) death related to tumor. A numeric sc ore was assigned to each unfavorable histopathologic feature. Low grad e tumors had scores of 0-4. Intermediate grade tumors scored 5 or 6. H igh grade tumors had scores higher than 6. RESULTS, Most patients (75% ) were tumor free after the initial treatment. Twenty-one patients (9% ) had local recurrence only, 12 (5%) demonstrated metastasis and survi ved, and 25 patients (11%) died of their disease. CONCLUSIONS. Clinica l features associated with metastasis or death were more advanced age, tumor size, and preoperative symptoms. Histopathologic features that correlated with poor outcome were cystic component less than 20%, 4 or more mitotic figures per 10 high-power fields, neural involvement, ne crosis, and anaplasia. All five of these histopathologic features demo nstrated statistical prognostic significance when parotid gland tumors from Groups 1 and 4 were compared (P < 0.001). The point-based gradin g system demonstrated a statistically significant correlation with out come for parotid tumors but not for submandibular tumors. The authors' findings indicate that patients with rumors of equal histopathologic grade have a better prognosis when their tumors are in the parotid gla nd than when their tumors are in the submandibular gland. Six of eight submandibular tumors that metastasized or resulted in death were low grade lesions, and none were high grade. (C) 1998 American Cancer Soci ety.