Facility-Level Variation of Low-Value Breast Cancer Treatments in Older Women with Early-Stage Breast Cancer: Analysis of a Statewide Claims Registry.

BACKGROUND: Since 2004, national guidelines have supported the omission of sentinel lymph node biopsy (SLNB) and radiotherapy for women ≥ 70 years of age with early-stage, hormone receptor-positive (HR+) breast cancer, but many women continue to receive at least one of these services. Provider- and patient-level factors may contribute to persistent utilization, but the role of facility-level factors is unknown. We aimed to determine facility-level variation of SLNB and adjuvant radiotherapy utilization in older women with early-stage, HR+ breast cancer undergoing breast-conserving surgery (BCS). Additionally, we aimed to explore factors associated with SLNB and radiotherapy utilization and the intra-facility correlation in their utilization. METHODS: We conducted a retrospective cohort study using a statewide registry of claims data. We included women ≥70 years of age diagnosed with breast cancer who underwent BCS from 2012 to 2019 at 80 hospitals in the Michigan Value Collaborative. The main outcome was inter-facility rates and variation of SLNB and radiotherapy, as well as intra-facility correlation in their utilization. RESULTS: The cohort included 7253 women (median age 77 years). Only 20% (n = 1440) underwent BCS alone, whereas 71% (n = 5122) underwent SLNB and 52% (n = 3793) received radiotherapy. Inter-facility rates of SLNB ranged from 35 to 82% (median 70%), and radiotherapy ranged from 19 to 72% (median 49%). SLNB and radiotherapy were positively correlated (r = 0.27, p = 0.016). CONCLUSIONS: SLNB and radiotherapy rates remain high with significant variation in utilization at the facility level. High utilizers of SLNB are likely to be high utilizers of radiotherapy, suggesting the opportunity for strategic targeting of these facilities and their clinicians.