Positive margin rates and predictors in transoral robotic surgery after federal approval: A national quality study

Abstract

BACKGROUND: Purpose of the study is to assess nationwide margin performance in oropharynx transoral robotic surgery (TORS). METHODS: Retrospective review of the National Cancer Database. RESULTS: Two thousand six hundred sixty-one patients were included. The national positive margin rate (PMR) was 16.9%. High-volume facilities had a lower PMR than low-volume facilities (12.7% vs 21.9%; P < .001). Patients with disease of the tonsil had a lower PMR (15.7%) than base-of-the-tongue (18.2%; P = .14). PMR increased with T classification (T1 = 13.0%, T2 = 17.1%, T3 = 28.2%, T4a = 45.9%, T4b = 58.3%; P < .001). On multivariable regression, factors associated with margin status included only lymph-vascular invasion (1.63[1.13-2.36]; P = .01), high volume (0.57[0.36-0.92]; P = .005), and T classification (as compared to T1, T2: 1.50[1.03-2.18], T3: 3.11[1.77-5.46], T4a: 7.03[2.95-16.75], T4b: 6.72[1.26-35.93]; P < .001). CONCLUSIONS: National PMR is 16.9%, substantially higher than reported in high-volume TORS centers. There is a linear association between positive margins and T classification, with T3 and T4 PMRs exceeding 28%. High-volume facilities are half as likely to yield positive margins compared to low-volume facilities. There was no association between human papilloma virus status, tumor subsite, or academic facility status and positive margins.