Preoperatively Diagnosed Versus Undiagnosed Major Salivary Gland Cancer: Clinicopathological Characteristics, Treatment Strategies, and Oncological Outcomes.

Abstract

To evaluate differences in clinicopathological characteristics, treatment strategies, and oncological outcomes between preoperatively diagnosed and undiagnosed major salivary gland cancers (MSGCs). Retrospective cohort study. A single tertiary academic hospital. Surgically confirmed MSGCs between 2012 and 2023 were included. The cohort was divided into the diagnosed and undiagnosed groups based on the preoperative diagnosis of MSGC determined by fine-needle aspiration cytology (FNAC) or core-needle biopsy. Clinicopathologic features, surgical strategies, and loco-regional control (LRC) were compared between the groups. A total of 122 patients were enrolled. Among those, 49 (40.2%) were diagnosed preoperatively, while 73 (59.8%) were undiagnosed. The undiagnosed group had a higher reliance on FNAC (93.2% vs 51.0%, P < .001) and higher proportions of low/intermediate-grade tumors (75% vs 26.5%, P < .001) and mucoepidermoid carcinoma (45.2% vs 18.4%, P < .001). These were verified as independent risk factors for preoperative undiagnosis in multivariate logistic regression analysis. The undiagnosed group was associated with delayed (60 vs 24 days, P < .001) and more limited surgical procedures, including lower frequency of near-total/total parotidectomy (23.3% vs 42.9%, P = .001) and elective neck dissection (26.5% vs 61.6%, P < .001), compared to the diagnosed group. Grade- and stage-matched analysis showed a trend towards worse LRC in the high-grade or advanced-stage undiagnosed MSGCs. Preoperatively undiagnosed MSGCs exhibit distinct clinicopathological characteristics, treatment strategies, and oncological outcomes compared to preoperatively diagnosed cases, highlighting the critical role of preoperative diagnosis in the management MSGCs.