e12694 Background: Ovarian function suppression (OFS) combined with endocrine therapy (ET) using tamoxifen or an aromatase inhibitor improves outcomes among premenopausal women with hormone receptor-positive breast cancer, particularly those with higher recurrence risk. More than a decade after initial publication of the SOFT and TEXT trials supporting OFS use, real-world adoption patterns and factors associated with OFS uptake over time remain incompletely characterized. Methods: We used the MarketScan healthcare claims database to identify women aged 18-49 with a breast cancer diagnosis who underwent lumpectomy or mastectomy between 2015 and 2023. Analyses were limited to women with commercial insurance and pharmacy coverage from one year before to two years after surgery. Women with a gynecologic cancer diagnosis or prior oophorectomy were excluded. OFS was defined as oophorectomy after surgery or receipt of >2 gonadotropin-releasing hormone agonist (GnRHa) injections. Adherence to ET was defined as proportion of days covered (PDC) >0.80 within the first year. Temporal trends in OFS use were assessed, and multivariable logistic regression was used to identify factors associated with OFS use. Results: We identified 14,949 women who met inclusion criteria. In the overall cohort, 2,988 (20.0%) women received OFS, with uptake increasing significantly over time from 15.5% in 2015 to 25.1% in 2023 (p < 0.001). This trend was driven by increased GnRHa use (8.9% in 2015 to 19.7% in 2023), with oophorectomy rates remaining stable (8.1% to 8.5%). Nearly half of all patients received chemotherapy (46.8%), predominantly in the adjuvant setting (43.4%). OFS use among adjuvant chemotherapy recipients increased from 29.3% to 50.8% over the study period (p < 0.001), again driven by increased GnRHa use (20.6% to 45.2%). Most patients initiated a GnRHa during adjuvant chemotherapy (76.6%), and among these, 84.2% continued the GnRHa after chemotherapy completion. After adjusting for baseline characteristics, OFS use was associated with younger age (35.1% for age 18-39 versus 16.9% for age 40-49; OR 1.94, 95% CI 1.75 – 2.16) and chemotherapy use (OR 11.28, 95% CI 10.05 – 12.67). Among our study population, 10,033 (67.1%) women received ET. Non-adherence to ET was slightly lower among those who underwent OFS (22.8% vs 25.4%, p = 0.01). Conclusions: Uptake of OFS among premenopausal women with breast cancer has increased substantially since 2015, although overall use remains low. By 2023, approximately one-quarter of the overall cohort and one-half of patients who received chemotherapy were treated with OFS. Notably, receipt of OFS was associated with lower rates of non-adherence to ET. Further research is needed to understand patient and treatment factors associated with OFS initiation and ET adherence, in order to optimize OFS use and improve outcomes in young women with breast cancer.
Tao et al. (Thu,) studied this question.