Preoperative biopsy in parotid malignancies: Variation in use and impact on surgical margins

Abstract

Objectives Determine rate of preoperative biopsy in parotid malignancies, identify factors associated with its use, and its association with surgical margins. Study Design Retrospective cohort. Setting Commission on Cancer–Accredited Institutions. Subjects and Methods We included 5533 patients treated surgically for a parotid malignancy 2004–2014 in the National Cancer Database. Chi‐squared tests, univariable, and multivariable logistic regressions were used to evaluate predictors of preoperative biopsy (defined as needle, aspiration, or incisional), and associate biopsy with surgical margins. Results Preoperative biopsy was utilized in 26.0% of patients. Biopsy was more likely in patients >60 years (odds ratio [OR]: 1.19, P = .035), advanced clinical T stage (vs. T1,T2 OR: 1.23, P = .009; T3 OR: 1.26, P = .026; T4A OR: 2.05, P < .001), advanced clinical N stage (vs. N0, N1: OR: 1.39, P = .013; N2/3: OR: 1.63, P < .001), in academic centers (OR: 1.18, P < .024), and in higher volume centers (vs. low, medium OR: 1.28, P = .002; high OR: 2.16, P < .001). Biopsy use increased over time (vs. 2004–2006, 2007–2010 OR: 1.20, P = .047; 2011–2014 OR: 1.39, P < .001). Biopsy was associated with a reduced risk of positive margins in patients with clinical T1 stage (OR: 0.70, P = .012), and younger than 61 (OR: 0.79, P = .036). Conclusion The national rate of preoperative biopsy in parotid malignancy is low at 26.0%, but has increased over time. Preoperative biopsy is associated with a reduced risk of positive margins in younger patients and those with early clinical stage, suggesting its increased use may improve surgical outcomes and decrease reoperation or adjuvant therapy in these subgroups of patients. Level of Evidence 3 Laryngoscope, 130:1450–1458, 2020