Abstract
Objective:To analyze the relationship between the optimal surgical margin value and clinical prognosis of transoral robotic surgery（TORS） in treating human papillomavirus（HPV） -positive oropharyngeal squamous cell carcinoma. Methods:A single-center, prospective, observational cohort study was conducted, enrolling patients with early and moderated stage（≤T3 stage） oropharyngeal carcinoma undergoing TORS between July 2020 and April 2024. The proposed optimal surgical margin cutoff value for TORS was set as 2 mm. The primary objectives were to evaluate the optimal clear margin for TORS and its association with overall survival（OS） and progression-free survival（PFS）. Logistic regression was used to analyze correlations between surgical margins and clinical variables, while Cox regression models assessed the impact of surgical margins on OS and PFS. Results:A total of 90 patients（60 males, 66.7%） were included, all had squamous cell carcinoma, with a mean age of 58.0±9.0 years（range: 39-84 years） old. The 1, 2 and 3-year OS rates were 92.3%, 89.9% and 85.0%, respectively, while the 1, 2 and 3-year PFS rates were all 90.1%. For surgical margins ≤2 mm, the 1, 2 and 3-year OS rates were 80.8%, 69.3% and 69.3%, respectively, and PFS rates were 77.9% across three time points. For surgical margins>2 mm, the 1, 2 and 3-year OS rates were 96.5%, 96.5% and 90.6%, respectively, with PFS rates of 94.6%. Logistic regression showed no correlation between surgical margins and tumor type, T/N stage, smoking, alcohol use, or gender（P>0.05）. Cox analysis identified surgical margins>2 mm as a significant factor improving PFS（HR=0.14, 95%CI 0.02-0.90, P=0.038）. Conclusion:This systematic analysis suggests setting a 2 mm and longer as clear surgical margin for TORS. Margins>2 mm are associated with superior postoperative PFS rate and prolonged PFS time in HPV-positive oropharyngeal carcinoma patients.