IntroductionChronic rhinosinusitis with nasal polyposis (CRSwNP) is often treated with endoscopic sinus surgery (ESS), however, patients may require revision surgery due to recurrence. To date, no studies have compared outcomes for combined surgery and biologic therapy for CRSwNP compared to biologic therapy alone.MethodsRetrospective case‐control study of CRSwNP patients who underwent ESS while on dupilumab or mepolizumab (ESS‐biologic cohort), compared to CRSwNP patients on biologic therapy (biologic‐only controls). Cohorts were matched according to indication, aspirin exacerbated respiratory disease (AERD), sinonasal outcome test‐22 (SNOT‐22), and total polyp scores.Results16 patients underwent ESS while on biologic therapy (13 dupilumab and 3 mepolizumab). 16 patients were biologic‐only controls. There were no significant differences between indication, baseline SNOT‐22 scores, polyp scores, and AERD status between cohorts. Patients underwent surgery a median of 33 days after starting biologic therapy. After 12 months of follow up, the total polyp score for the ESS‐biologic cohort decreased from 4.73 to 0.09, compared to biologic‐only controls 5.22 to 3.38 (95% CI of Difference: ‐5.37 to ‐1.38, Cohen's d: 2.40, p = 0.005). In the ESS‐dupilumab sub‐analysis, the ESS‐dupilumab cohort had a significant reduction in polyp burden 4.85 to 0.00 compared to controls 4.88 to 3.50 (95% CI of Difference: ‐5.68 to ‐1.32, Cohen's d: ‐1.69, p = 0.009).ConclusionIn CRSwNP patients, combined ESS and biologic therapy results in a significant and sustained decrease in polyp burden compared to biologic therapy alone. Larger studies are warranted to further examine the impact of combined therapy.This article is protected by copyright. All rights reserved