Prognosis of South Asian Buccal Mucosa Cancer Patients in the United States: Association of Race with Overall Survival

Background: Squamous Cell Carcinoma (SCC) of the buccal mucosa and gingiva accounts for approximately 10% of oral and pharyngeal cancers diagnosed in the United States each year, with a disproportionally higher incidence in individuals of South Asian descent. However, little has been documented regarding trends pertaining to overall survival. Thus, this research serves to identify predictors of survival and determine if overall survival (OS) differs for South Asians compared to other races once they develop non-metastatic buccal mucosa or gingiva squamous cell carcinoma. Methods: A population-based, cohort study of patients registered in the National Cancer Database® (NCDB) between the years 2004-2016 was performed. Kaplan-Meyer Survival Curves were executed to examine overall survival, while univariable (UVA) and multivariable analysis (MVA) was performed to determine the effect of multiple variables on OS. Results: South Asians had longer median OS at 88.7 months, compared to 58.6 months and 38.3 months for Caucasians and African Americans respectively (p<0.001). In UVA, race was highly significant, but when the cohort was selected to include only those who had undergone surgical resection, no statistically significant difference remained. On MVA, lack of surgery, older age, higher grade, higher T and N stage, use of chemotherapy, higher comorbidity scores were associated with worse OS, but race was not significant. Conclusion: South Asians in the US with non-metastatic buccal mucosa or gingiva SCC have better OS compared to Caucasians or African Americans, likely due to younger age at diagnosis (median 59 vs. 71 and 62 years old) and more frequent surgical resection (75% vs. 72% and 64%). In MVA, South Asians have similar OS as Caucasians.