(0681) Missed Adjuvant Therapy After Resection of Intermediate and High-Risk Oral Cavity Cancer: A Multi-Institutional Study

Introduction: Patients who have intermediate or high-risk features after resection of oral cavity squamous cell carcinoma (SCCa) should be treated with guideline-recommended adjuvant therapy to reduce the risk of disease recurrence, however many patients do not receive the indicated therapy.

Methods: A retrospective, multi-institutional cohort study investigating patients treated from November 2008 to November 2022 was completed. Study population included patients undergoing oncologic resection for previously untreated oral cavity SCCa. Primary outcome was receipt of guideline-recommended adjuvant radiation or chemoradiation therapy. Secondary objective was to evaluate associations between missed adjuvant therapy and survival. Univariable and multivariable logistic regression was used to identify patient, tumor, and treatment factors associated with receipt of adjuvant therapy. Cox proportional hazard analysis was used to identify associations between patient, tumor, and treatment factors and survival.

Results: A total of 342 patients were included; 197 had intermediate-risk disease and 145 had high-risk disease. Among all patients, 269 (78.7%) completed at least adjuvant radiation therapy. Among high-risk patients, 80 (55%) received adjuvant chemoradiation. On multivariable analysis, older patients were less likely to complete adjuvant therapy (OR 0.92, 95% CI 0.89-0.95, p < 0.001), as were patients who drove greater than 50 miles to their site of surgery (OR 0.36, 95% CI 0.19-0.66, p = 0.001). Among all 342 patients, receipt of adjuvant radiation (HR 0.21, 95% CI 0.10-0.45, p < 0.001) and receipt of adjuvant chemoradiation (HR 0.25, 95% CI 0.13-0.49, p < 0.001) were associated with improved overall survival.

Conclusions: After resection of intermediate and high-risk oral cavity SCCa, a significant proportion of patients do not receive appropriate adjuvant therapy. Older patients who travel farther for treatment may be at higher risk of missing adjuvant therapy after oral cavity resection, and missed adjuvant therapy is associated with worse overall survival.