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

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.