(A637) Survival Difference Between Advanced Oral Cavity Squamous Cell Carcinoma Treated with Surgery versus Definitive Chemoradiation

Introduction: Surgery remains the mainstay of treatment for oral cavity squamous cell carcinomas (OCSCC). In locoregionally advanced T3/T4 tumors, surgery can have devastating functional outcomes. Patients may be offered organ-preserving, definitive chemoradiation (CRT) therapy as an alternative to surgery in these cases. The aim of this study was to evaluate the overall survival (OS) of patients with T3/T4 OCSCC who underwent surgery with or without induction chemotherapy versus definitive CRT.

Methods: Retrospective cohort study of patients diagnosed with OCSCC from 2004 to 2020 was conducted using the National Cancer Database (NCDB). The database was queried for patients of all ages diagnosed with SCC of any oral cavity subsite. Patients were stratified to surgery upfront (with or without induction) or definitive CRT. Descriptive, univariable, multivariable, and survival analysis were performed in R version 4.3.0.

Results: 1912 patients with advanced stage (T3/T4) OCSCC were identified (mean [SD] age, 64.0 [11.3] years; 1229 [64.3%] male; 1576 [82.4%] white). 1876 patients underwent surgery upfront or surgery following systemic induction therapy and 36 patients underwent definitive CRT. There was no difference in 3-year OS between the surgery (56.8% [54.3-59.3%]) and CRT (47.4% [27.8-64.8%]) groups, p=0.49. Multivariate cox regression analysis controlling for age, sex, comorbidities, and tumor stage did not demonstrate any difference in OS between patients treated with upfront surgery compared to those who received induction followed by surgery (HR 0.64 [0.35-1.16], p=0.14) or definitive CRT (HR 1.23 [0.63-2.39], p=0.55).

Conclusions: Definitive CRT can be used as an alternative to surgery in T3/T4 tumors to maintain function with no compromise on survival.