Trismus, defined as restricted mouth opening, is a common complication among Taiwanese oral cancer patients, especially those who chew betel quid. However, the impact of trismus on survival outcomes in oral cancer patients undergoing transoral robotic surgery (TORS) is unclear. This study aimed to investigate the associations between trismus and surgical outcomes in Taiwanese male oral cancer patients treated with TORS. We conducted a retrospective propensity score-matched cohort study of 40 Taiwanese male oral cancer patients who underwent TORS between 2016 and 2022. Overall, 20 patients with trismus were matched to 20 patients without trismus. TORS achieved similar operative and short-term clinical outcomes in trismus patients to non-trismus patients. There were no significant differences between groups in operation time, blood loss, margin status, flap reconstruction rates, duration of nasogastric tube feeding, or length of hospital stay. Kaplan-Meier and Cox proportional hazard regression analyses were performed to compare overall survival (OS) and disease-free survival (DFS) between the two groups. The overall survival (OS) rate at three years was significantly lower in patients with trismus than those without trismus (27.1% vs. 95.0%, log-rank p = 0.02). However, there was no significant difference in disease-free survival (DFS) rates between the trismus and non-trismus groups (36.6% vs. 62.7%, log-rank p = 0.87). After adjusting for confounders, trismus was independently associated with a 13-fold increased risk of mortality (adjusted HR 12.87, 95% CI 1.55-106.50, p < 0.05). In conclusion, trismus appears to be an independent prognostic factor for reduced long-term OS in Taiwanese male oral cancer patients undergoing TORS, though short-term surgical outcomes were non-inferior in the trismus patients. Further research is warranted to clarify the mechanisms linking trismus and survival in this population.
Keywords: betel quid; concurrent chemoradiotherapy; disease-free survival; oral cancer; overall survival; propensity score matching; radiotherapy; transoral robotic surgery (TORS); trismus.