Treatment Factors Associated With Survival in Early-Stage Oral Cavity Cancer

IMPORTANCE: Most patients with oral cavity squamous cell cancer (OCSCC) are initially seen at an early stage (I and II). Although patient and tumor prognostic features have been analyzed extensively, population-level data examining how variations in treatment factors impact survival are lacking to date. OBJECTIVE: To analyze associations between treatment variables and survival in stages I and II oral cavity squamous cell carcinoma. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of cases in the National Cancer Data Base. Patients diagnosed as having stage I or II OCSCC between January 1, 2003, and December 31, 2006, and treated with surgery were identified. Univariate and multivariable analyses of overall survival based on patient, disease, and treatment characteristics were conducted. MAIN OUTCOMES AND MEASURES: Overall survival and survival at 5 years. RESULTS: In total, 6830 patients were included. Survival at 5 years was 69.7% (4760 patients). On univariate analysis, treatment factors associated with improved survival included treatment at academic or research institutions, no radiation therapy, no chemotherapy, and negative margins (P < .001 for all). Neck dissection was associated with improved survival (P = .001), reflecting pathologic restaging and elimination of patients with occult nodal disease. Patients treated at academic or research institutions were more likely to receive neck dissection and less likely to receive radiation therapy or have positive margins. On multivariable analysis, neck dissection (hazard ratio HR, 0.85; 95% CI, 0.76-0.94; P = .003) and treatment at academic or research institutions (HR, 0.88; 95% CI, 1.01-1.26; P = .03) were associated with improved survival, whereas positive margins (HR, 1.27; 95% CI, 1.08-1.49; P = .005), insurance through Medicare (HR, 1.45; 95% CI, 1.25-1.69; P < .001) or Medicaid (HR, 1.96; 95% CI, 1.60-2.39; P < .001), and adjuvant radiation therapy (HR, 1.31; 95% CI, 1.16-1.49; P < .001) or adjuvant chemotherapy (HR, 1.34; 95% CI, 1.03-1.75; P = .03) were associated with compromised survival. CONCLUSIONS AND RELEVANCE: Prognostic impacts of treatment factors in early OCSCC are presented. Overall survival for early OCSCC varies with demographic and tumor characteristics but also varies with treatment and system factors, which may represent targets for improving outcomes in this disease.