Going Off Guidelines: An NCDB Analysis of Missed Adjuvant Therapy Among Surgically Treated Oral Cavity Cancer

Abstract

Objective: Patient factors associated with failure to receive adjuvant therapy after oral cavity cancer resection remain understudied. Here, we identified rates of missed adjuvant therapy, determined factors associated with missed therapy, and assessed associations with survival.

Study design: Retrospective cohort.

Setting: National Cancer Database.

Methods: Patients with resected oral cavity squamous cell carcinoma and known adjuvant therapy status were included. T3-4 stage, N2-3 stage, and lymphovascular invasion were considered indications for adjuvant radiation. Extranodal extension or positive margins were considered indications for chemoradiation. Patient factors were examined for associations with missed adjuvant therapy. Overall survival was evaluated by Cox proportional hazard analysis.

Results: A total of 53,503 patients were included. 27.5% missed adjuvant therapy altogether, and 26.7% with a documented indication for chemoradiation missed chemotherapy. Factors associated with missed adjuvant therapy were age, white race, low income, metropolitan population, increasing comorbidities, travel distance, lip primary, and treatment at the academic facility. Factors associated with missed chemotherapy were age, female sex, nontongue subsite, and treatment at a nonacademic center. Among patients with indications for adjuvant radiation, missed radiation was associated with worse overall survival (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.31-1.53). Among patients with indications for adjuvant chemoradiation, missed chemotherapy was associated with worse overall survival (HR: 1.19, 95% CI: 1.09-1.29).

Conclusion: Missed adjuvant therapy occurs frequently after oral cavity resection. Patients treated at academic centers may be at risk of missed therapy related to travel distance, though these patients are more likely to receive adjuvant chemotherapy when indicated. Missed adjuvant therapy is associated with worse survival.

Keywords: adjuvant chemoradiation; adjuvant radiation; oral cavity squamous cell carcinoma; treatment guidelines.