Clinical utility of sentinel lymph node biopsy in women ≥ 70 years with early breast cancer.
Authors: Merh Radhika , Vorburger Denise , Ranger Alison , Kipps Emma L. S. , Parton Marina , Tasoulis Marios Konstantinos 
Published: June 2023

e12512 Background: Sentinel lymph node biopsy (SLNB) has traditionally been used to stage the axilla in early breast cancer (EBC) to guide adjuvant treatment recommendations. Following advances in genomic testing and tumor biology understanding, its role may be less critical especially in selected groups of women. The aim was to evaluate clinical utility of SLNB in adjuvant treatment recommendations for women ≥ 70 years with EBC in a tertiary unit in the United Kingdom. Methods: Retrospective cohort study of women ≥ 70 years with cT1-2N0 EBC undergoing primary surgery and SLNB between 01/2018-12/2022. Simple descriptive statistics and non-parametric tests were performed, including cost analysis of the SLNB procedure. Results: A total of 528 patients were included. The median age was 75 (IQR 72-79) years. Most cancers were invasive ductal (84.7%), grade 2 (66.9%), hormone receptor (HR) positive/HER2 negative (84.4%) with a median tumor size of 17 (IQR 4-50) mm. SLNB was positive in 64 (12.1%) patients. Of these 64 patients, 13 (20.3%) had completion ALND and 39 (60.9%) had adjuvant locoregional nodal radiotherapy (RT) including levels 1 & 2 of the axilla; adjuvant RT to levels 3 & 4 after ALND was given to 5/13. As per ACOSOG Z0011 criteria, 2/13 could have been spared ALND and 31/39 axillary RT. The multidisciplinary team (MDT) recommended adjuvant chemotherapy (AC) in 72 (13.6%) patients and 45 received it. Of those with a positive SLNB (n = 64), AC was recommended in 15, and received by 11. Recommendation for AC was significantly associated with age (p = 0.006), tumor grade (p < 0.0001), size (p = 0.001), receptor status (p < 0.0001) and positive SLNB status (p = 0.02) but not with comorbidities (p = 0.06). A subgroup analysis of 294 patients with cT1N0, HR+/HER2- EBC, representing a more favorable prognosis group, was performed. Here, 31/294 (10.5%) patients had positive SLNB, of whom 5 underwent ALND and 16 regional nodal RT, where 2/5 could have been spared ALND and 13/16 axillary RT as per ACOSOG Z0011 criteria. AC was recommended in 11/294 (3.7%) women and 9 received it. AC was not recommended in 20/31 (64.5%) cases, despite a positive SLNB. MDT recommendation for AC was associated with SLNB status (p = 0.02), grade 3 (p = 0.002) and multifocal disease (p = 0.02), while AC receipt was only associated with grade 3 (p = 0.017) and multifocal disease (p = 0.009) but not SLNB status (p = 0.058). Given an average cost of $6504.95 / £5359.38 per SLNB procedure in this unit, avoiding routine SLNB in the subgroup population may have potentially saved $1,912,493.95 / £1,575,657.72 in this 5 year period. Conclusions: Only a small proportion of women ≥ 70 years with EBC had positive SLNB that may influence adjuvant treatment recommendations, especially with favorable prognosis tumors. In such cases, where clinical morbidity and financial burden of SLNB may outweigh the benefits, a nuanced discussion for opting in SLNB rather than routine performance should be considered.