The association of ethnicity and oncologic outcomes for oral cavity squamous cell carcinoma (OSCC)

Objective: To compare oncologic outcomes of South Asian (SA) patients treated at a regional cancer centre in Canada, for oral squamous cell carcinoma (OSCC), to the general population. Methods: Adult patients who underwent primary surgical resection of OSCC +/- adjuvant treatment between 2009 and 2022 (N=697) were included. SA patients were identified using a validated method and compared to non-SA patients. Baseline characteristics, including betel nut consumption, were compared, and disease-specific survival (DSS) and recurrence-free survival (RFS) were evaluated using Kaplan-Meier methods, with median follow-up time of 36.4 months [SD 31.02]. Cox proportional hazard regression models adjusted for potential confounders. A p-value < 0.05 was considered statistically significant. Results: SA patients (9% of cohort, n = 64) were significantly younger and had lower rates of smoking and alcohol consumption compared to non-SA patients. There were no differences in tumor characteristics or the use of adjuvant radiation. SA patients had a two-fold higher risk of recurrence and significantly worse disease-specific survival, even after adjusting for stage and high-risk features [RFS: HR 2.01(1.28 - 3.14), DSS: HR 1.79(1.12 - 2.88)]. The consumption of betel nut was not associated with outcomes. Conclusion: To our knowledge, this study is the first to compare the oncological outcomes of SA patients with OSCC to non-SA patients. SA patients had significantly worse outcomes, even after controlling for known predictors of recurrence and disease-specific survival. These findings can inform personalized treatment decisions and influence public health policies when managing patients with different ethnic backgrounds.