(0709) Predictors of Metastasis in Head and Neck Salivary Acinic Cell Carcinoma

Introduction: Head and neck salivary acinic cell carcinoma is rarely considered as a malignancy with increased risk of metastasis. However, research has shown a subset of these high-grade tumors that may have prolonged metastatic potential. This study aims to understand risk factors for metastasis in head and neck salivary acinic cell carcinoma.

Methods: Utilizing the SEER database, we conducted a population-based analysis on head and neck acinic cell carcinoma cases (2000-2019), considering key variables such as age at diagnosis, gender, race, TNM staging, survival months, and cause of death. Cases with unknown cause of death and TNM stages were excluded. Statistical analyses included t-tests, ANOVA, Kaplan-Meier survival, and log-rank analyses.

Results: In total, 1,642 patients were identified, among which, 1.2% exhibited metastasis and were associated with older age (p < 0.05) and male gender (p < 0.05). M1-staged patients (average age 62.38 years at diagnosis) had reduced survival (p < 0.05) and higher cancer-related mortality (p < 0.05) than M0 (average age 51.32). In the M1 group, 85% had initial T>1 and 66.7% had initial N≥1, showing significantly higher initial T (p < 0.05) and N values (p < 0.05) than M0. Kaplan Meier and log-rank analyses revealed diminished survival in males (p < 0.05), Caucasians (p < 0.05), and M1 cases (p < 0.001).

Conclusions: Acinic cell carcinoma is rarely identified as having metastatic disease. Predictors of metastasis include older age, male gender, and higher T and N stage on initial diagnosis. Additionally, male gender, Caucasian race and presence of metastasis were significantly associated with decreased survival time compared to their counterparts. This study emphasizes the need for more research into the delayed metastatic potential of acinic cell carcinoma.