Introduction: The 2016 National Comprehensive Cancer Network Clinical Practice Guidelines for head and neck cancer recommend primary surgical resection for resectable oral cavity tumors, with primary radiation therapy (RT) reserved for medically inoperable patients, those who refuse surgery, and occasionally for early-stage malignancies. To our knowledge, few contemporary studies have been conducted to compare surgical versus non-surgical therapy for oral cavity squamous cell carcinoma on a national level.
Objectives: 1) To describe the incidence of non-surgical treatment regimens for patients diagnosed with oral cavity squamous cell carcinoma (SCC); 2) to identify factors associated with increased likelihood of undergoing primary radiation therapy (RT) or chemoradiotherapy (CRT) for oral cavity SCC; and 3) to determine whether primary RT/CRT is associated with worse survival.
Study design: Retrospective national database research study
Methods: The National Cancer Data Base was utilized to identify all patients diagnosed with oral cavity squamous cell carcinoma from 1998-2011. Primary surgical resection with or without adjuvant therapy was compared to primary RT or CRT. Univariate analysis by chi-square and logistic regression and multivariate analysis by binary logistic regression were used to identify factors associated with increased likelihood of undergoing primary RT instead of surgical resection. Kaplan-Meier analysis and Cox proportional hazards models were generated to analyze the association between treatment modality and overall survival (OS).
Results: Of the 27,120 patients included in the final analysis, 5,378 (19.8%) underwent primary RT or chemoradiotherapy (CRT). In 1998, 21.8% of patients underwent non-surgical treatment for oral cavity cancer, which decreased to 14.8% by 2009. On multivariate analysis, older age, non-white race, male sex, payment methods other than private insurance, treatment facility in the Northeast, increasing T classification, and late-stage cancer were associated with increased likelihood of undergoing primary RT. Patients treated at comprehensive community cancer programs (OR 0.84, p=0.01) and academic/research programs (OR 0.31, p<0.001) were more likely to undergo surgical resection. Malignancies of the floor of mouth (OR 1.18, p=0.001), hard palate (OR 1.49, p<0.001), buccal mucosa (OR 1.27, p=0.001), and retromolar trigone (OR 2.18, p<0.001) were significantly more likely to undergo nonsurgical treatment. On Cox proportional hazards model analysis, primary RT/CRT was significantly associated with decreased OS (HR=1.91, p<0.001); this was upheld in subgroup analysis of patients with early-stage disease (HR 1.85, p<0.001). For all malignancies, 5-year OS was 55.4% vs. 17.4% for patients undergoing surgical resection vs. primary RT/CRT; 5-year OS for surgery and primary RT/CRT for early-stage malignancies was 64.6% and 25.6%, respectively.
Conclusion: A number of factors are associated with patients undergoing primary radiation therapy/chemoradiotherapy instead of primary surgical resection. However, surgical resection for primary treatment of oral cavity cancer, regardless of clinical stage, is significantly associated with improved overall survival.