Real-World Clinical, Enviro-Logistical and Economic Implications of Sentinel Lymph Node Biopsy Omission in Early Breast Cancer.

BACKGROUND: The randomized INSEMA, SOUND, and BOOG 2013-08 trials demonstrated oncologic non-inferiority of omitting sentinel lymph node biopsy (SLNB) for selected patients with biologically favorable early breast cancer (eBC). However, real-world implementation and the associated clinical, economic, and environmental implications remain unclear. METHODS: A retrospective cohort study analyzed patients with eBC treated at a certified tertiary breast cancer center (2018-2020). Eligibility for SLNB omission was determined according to current guidelines (cT1, cN0, HR+/HER2-, grades 1 and 2, age ≥ 50 years). Clinical upstaging rates were assessed. Time toxicity was derived from prospectively collected nuclear medicine workflow data. Environmental impact was quantified using a process-based carbon footprint analysis of 99mTc-guided SLNB. Economic implications were modeled within the German diagnosis-related-groups-reimbursement framework. National extrapolations were performed using registry incidence data. RESULTS: Of 885 patients, 248 (28%) fulfilled the omission criteria. Postoperative upstaging to ≥ pT2 occurred for 14.9% and to pN+ for 13.3% of the patients, with no significant difference between lobular and no-special-type subtypes (p = 0.31). Marking of SLNB resulted in 2.18 h of additional patient time burden, and associated waste generated 0.54 kg of CO2 equivalents. Extrapolated nationally, the data show that approximately 19,330 patients could avoid SLNB annually, corresponding to 10.4 tons of CO2 equivalents and 1.8 tons of waste per year. Although case-based reimbursement decreases by 22.6%, omission liberates 52.5 h of annual operating room capacity. CONCLUSIONS: Nearly one third of patients with eBC qualify for SLNB omission according to current guidelines. Beyond oncologic safety, this strategy reduces patient time toxicity, environmental burden, and resource utilization, supporting axillary de-escalation as a model of sustainable and value-based surgical oncology.