Prognostic factors in surgically treated malignant salivary gland tumors.

OBJECTIVES:To identify prognostic factors for evidence-based risk stratification in malignant salivary gland tumors. METHODS:This retrospective study identified 162 patients who presented with malignant salivary gland tumors between 2010 and 2020. Final analysis included 91 patients who underwent surgical treatment at our institution and were followed-up for ≥ 1 year. Medical records were reviewed and patients were categorized according to their risk profile. RESULTS:This study included 91 patients (51 males, 40 females, mean age 61 years). The most frequent entities were adenoid cystic carcinoma (n = 13, 14.3%) and mucoepidermoid carcinoma (n = 12, 13.2%). Kaplan-Meier analysis demonstrated a five-year overall survival (OS) of 66.2% and a recurrence-free survival (RFS) of 50.5%. Age > 60 years (p = 0.011), categorization into high-risk group (p = 0.011), UICC stage (p = 0.020), T stage (p = 0.032), grading (p = 0.045) and vascular invasion (p < 0.001) were significantly associated with OS; age > 60 years (p = 0.014), categorization into high-risk group (p < 0.001), UICC stage (p = 0.021), T stage (p = 0.017), grading (p = 0.011), vascular invasion (p = 0.012) and lymphovascular invasion (p < 0.001) were significantly associated with RFS. Multivariate Cox regression with backward elimination identified T stage (HR 1.835; 95% CI 1.187-2.836; p = 0.006) and grading (HR 2.233; 95% CI 1.113-4.480; p = 0.024) as significant factors for OS. Grading (HR 2.499; 95% CI 1.344-4.648; p = 0.004) was confirmed as a significant factor for RFS. CONCLUSION:Considering the risk of recurrence and distant metastasis in malignant salivary gland tumors, locoregional surgical control may not be sufficient and adjuvant therapies such as radiotherapy and/or systemic therapies should be considered.