Missed Adjuvant Therapy After Resection of Intermediate and High‐Risk Oral Cavity Cancer: A Multi‐institutional Study

Objective Identify the proportion of patients who do not receive recommended adjuvant therapy after resection of oral cavity squamous cell carcinoma (SCCa) and factors associated with missed therapy. Evaluate associations between missed adjuvant therapy and survival. Study Design Retrospective, multi‐institutional cohort study. Setting Three tertiary care centers. Methods Patients with resected oral cavity SCCa and known adjuvant therapy status were included. Intermediate‐risk features (T3‐4 stage, N2‐3 stage, perineural, or lymphovascular invasion) were indications for adjuvant radiation, whereas high‐risk features (extranodal extension or positive margins) were indications for adjuvant chemoradiation. Logistic regression was used to examine factors associated with adjuvant therapy initiation, and survival was analyzed using Kaplan‐Meier and Cox proportional hazard models. Results In total, 361 patients were included; 206 had intermediate‐risk disease, and 155 had high‐risk disease. In total, 284 (79%) completed adjuvant radiation, and 91 (58%) high‐risk patients received chemoradiation. The most documented reason for not initiating adjuvant therapy was patient refusal. On multivariable analysis, older patients were less likely to complete adjuvant therapy (odds ratio [OR] 0.93 per year, 95% CI 0.90‐0.95, P < .001) as were those traveling >50 miles for surgery (OR 0.49, 95% CI 0.26‐0.89, P = .02). Receipt of adjuvant radiation (hazard ratio [HR] 0.22, 95% CI 0.11‐0.45, P < .001) and chemoradiation (HR 0.23, 95% CI 0.12‐0.43, P < .001) were associated with improved overall survival. Conclusion A significant proportion of oral cavity SCCa 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.