Prognostic Factors and Outcome Analysis of Submandibular Gland Cancer: A Clinical Audit

Abstract

To retrospectively review a long-term, single-institution experience of subjects with submandibular gland malignancies treated with definitive locoregional therapy with an aim to identify clinicopathologic variables that correlate with outcomes. A comprehensive chart review of 47 patients presenting to the institute from 1993 to 2005 with a histologic diagnosis of submandibular salivary gland cancer was performed to extract demographic data, clinicopathological characteristics, and treatment details. Clinical and pathologic factors were correlated with locoregional control, distant metastases free survival, and disease-free survival using log-rank test and Cox proportional hazards model for univariate and multivariate analysis, respectively. With a median follow-up of 29 months (interquartile range, 13 to 64 months), the actuarial 5-year locoregional control, distant metastasis-free survival, and disease-free survivals of the entire cohort were 80.5%, 86.1%, and 71.8%, respectively. Overall stage grouping (P = .008), perineural invasion (P = .04), and radiotherapy dose (P = .033) were significant predictors of locoregional control. Overall stage grouping (P = .014) and T stage (P = .05) also affected disease-free survival. Extraglandular involvement showed a trend toward poorer outcome. Submandibular gland cancer is a rare disease with histologic diversity and variable clinical behavior. Overall stage grouping and perineural invasion remain the most significant predictors of outcome. Adequate doses of adjuvant radiotherapy improve locoregional control in high-risk patients.