Can the tumor site affect the prognosis of salivary gland cancer? a systematic review and meta-analysis

Objectives To assess the association between primary sites of salivary gland tumors (SGTs) and prognosis. Study Design Studies from 5 databases were assessed and a meta-analysis was performed using studies that presented 95% CI, hazard ratio (HR), and survival analysis. QUIPS (Quality in Prognosis Studies) was used to assess the methodological quality of included studies, and GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) was used to assess the quality of evidence. Results Results from 46,361 patients showed that site had a prognostic effect on SGTs. Tumors involving minor salivary glands showed worse overall survival (HR = 1.60; 95% CI, 1.17-2.19; P = .003), disease-specific survival (HR = 1.63; 95% CI, 1.12-2.37; P = .01), and cause-specific survival (HR = 2.10; 95% CI, 1.72-2.55; P = .00001). Tumors from major salivary glands showed better recurrence-free survival (HR = 2.31; 95% CI, 1.77-3.02; P = .00001) and locoregional control of disease (HR = 2.66; 95% CI, 1.20-5.91; P = .02). Conclusions Our results showed that the primary site of SGTs has an effect on survival and patient prognosis.