Prognostic impact of resection margin involvement in surgically managed HPV-positive tonsil cancer

Objectives: To find out the role of resection margin involvement in surgically managed HPV-positive tonsil cancer. Materials and methods: The study included 94 subjects with HPV-positive tonsil cancer undergoing surgical treatment. We evaluated the relationships between the resection margin status, clinicopathological factors, and oncological outcome. Results: The rate of resection margin involvement was 22.3% (21/94) after ablative surgery. Margin involvement, lymphatic invasion, and extracapsular spread were associated with the 5-year disease-free survival (DFS) and disease-specific survival (DSS) rate in univariate analysis. Multivariate Cox regression analysis confirmed a significant association between the margin involvement and 5-year DFS rate (HR = 4.602; 95% CI = 1.202-17.620; p = 0.026) and 5-year DSS rate (HR = 12.826; 95% CI = 1.399-117.593; p = 0.024). The incidence of resection margin involvement was significantly higher in patients with larger tumors (35.19 +/- 15.07 mm vs. 25.53 +/- 10.32 mm, p = 0.011) and more invasive tumors (17.84 +/- 7.90 mm vs. 13.46 +/- 6.88 mm, p = 0.037). The cutoff value of tumor size and depth of invasion for resection margin involvement was 29.5 mm (74% sensitivity and 63% specificity) and 14.5 mm (74% sensitivity and 61% specificity), respectively. Conclusion: Resection margin involvement was significantly correlated with tumor size and the depth of invasion in HPV-positive tonsil cancer. Furthermore, resection margin involvement was associated with adverse outcomes.