BackgroundTheChoosing Wiselyinitiative recommended the omission of routine sentinel lymph node biopsy (SLNB) in patients ≥ 70 years of age, with clinically node-negative, early stage, hormone receptor (HR) positive and human epidermal growth factor receptor 2 (Her2) negative breast cancer in August 2016. Here, we assess the adherence to this recommendation in a Swiss university hospital.MethodsWe conducted a retrospective single center cohort study from a prospectively maintained database. Patients ≥ 18 years of age with node-negative breast cancer were treated between 05/2011 and 03/2022. The primary outcome was the percentage of patients in theChoosing Wiselytarget group who underwent SLNB before and after the initiative went live. Statistical significance was tested using chi-squared test for categorical and Wilcoxon rank-sum tests for continuous variables.ResultsIn total, 586 patients met the inclusion criteria with a median follow-up of 2.7 years. Of these, 163 were ≥ 70 years of age and 79 were eligible for treatment according to theChoosing Wiselyrecommendations. There was a trend toward a higher rate of SLNB (92.7% vs. 75.0%,p= 0.07) after theChoosing Wiselyrecommendations were published. In patients ≥ 70 years with invasive disease, fewer received adjuvant radiotherapy after omission of SLNB (6.2% vs. 64.0%,p< 0.001), without differences concerning adjuvant systemic therapy. Both short-term and long-term complication rates after SLNB were low, without differences between elderly patients and those < 70 years.ConclusionsChoosing Wiselyrecommendations did not result in a decreased use of SLNB in the elderly at a Swiss university hospital.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12957-023-03062-1.