23 Implementation of Choosing Wisely: Recommendations for Omission of Sentinel Lymph Node Biopsy in Elderly Patients With Early-Stage Breast Cancer

Background

The Society of Surgical Oncology Choosing Wisely (CW) initiative recommends against routine sentinel lymph node biopsy (SLNB) in women greater than or equal to 70 years of age with clinically node-negative, hormone receptor–positive, HER2-negative breast cancer. This is supported by randomized trial data, which showed no survival disadvantage and low axillary recurrence rates. However, without SLNB data for definitive staging, adjuvant treatment recommendations may change. This study assesses SLNB performance at our institution in accordance with CW guidelines, identifies predictive variables for SLNB, and evaluates trends in SLNB omission.

Methods

A retrospective review was performed from January 2021 to December 2023. We included patients aged 70 years or older with estrogen receptor/progesterone receptor–positive, HER2-negative, grade 1-2, T1/T2, clinically node-negative invasive breast cancer. Patients with clinically node-positive, triple-negative, HER2-positive, grade 3, T3 or T4 cancers, or lymphovascular invasion were excluded. We determined the rate of omission of SLNB, differences in tumor characteristics, and treatment between cohorts, and identified predictors of SLNB using multivariate logistic regression analysis.

Results

Of the 364 patients included, 211 (58.1%) underwent SLNB compared with 153 (41.9%) in the omission group. There was a statistically significant decrease in SLNB from 2021 to 2023 (72.3% to 39%; P <.0001; Figure). There was no significant difference in SLNB omission with respect to histological subtypes or T-stage. There was no difference in the number of patients who received radiation, or type (whole vs partial breast) in either cohort. Predictors of SLNB were younger age (<80 years; OR, 0.3; 95% CI, 0.2-0.6; P <.001), earlier year of diagnosis (P <.0001), and additional preoperative imaging. Those with SLNB were more likely to have additional pre-operative imaging, with 79% of patients undergoing at least an ultrasound evaluation of the axilla; this cohort was also more likely to have both ultrasound and MRI preoperatively (OR, 3.0; 95% CI, 1.5-6.1; P = .002). All 211 patients who underwent SLNB also underwent oncotype testing (OR, 2.4; 95% CI, 1.4-4.3; P = .003); however, only 37.4% was performed prior to surgery.

Of the 153 patients in the omission group, 2 (1.3%) returned to the operating room for SLNB. Of the 211 patients with initial SLNB, 10 (4.7%) underwent axillary dissection, and 13 (6.2%) received chemotherapy.

Conclusion

Since 2021, our institution has seen progressive adoption of the CW guidelines for omission of SLNB. Key predictors for performing SLNB in this cohort were younger age and earlier year of diagnosis, reflecting the willingness to incorporate this recommendation into practice over the 3-year study period.
Patients who underwent SLNB were more likely to have additional preoperative imaging and oncotype testing. This suggests additional factors, aside from tumor size and age, may have influenced the decision to omit axillary staging. This correlation is under further analysis to answer 2 important questions: does up-front oncotype testing and/or the absence of lymphadenopathy on imaging influence the decision to omit SLNB? It is likely that concerning preoperative imaging or equivocal oncotype scores may have prohibited SLNB omission, as axillary staging in those scenarios would provide valuable data to inform adjuvant treatment recommendations.

Notably, there was no difference in recurrence rates between the two cohorts; however, results are limited due to short follow-up. It is expected that our institutional trend towards omission of SLNB will continue to increase; this is further supported by the SOUND and INSEMA trials demonstrating safety in omission of axillary staging in younger patients with similar early breast cancers. Further research may examine the effect of axillary staging on adjuvant treatment decisions, weighing the balance of surgical de-escalation with potential undertreatment.