Health economic impact of breast cancer index (BCI) in patients with hormone responsive breast cancer (HRBC) considering extended adjuvant endocrine therapy (EET).

Abstract

25 Background: Previous research has demonstrated the benefit of EET for HRBC, however, the absolute benefit is modest and commits women to an extra 5 yrs of treatment. The Breast Cancer Index (BCI) is a gene expression-based test that has been validated to quantify the risk of late recurrence (BCI subscore) and to predict likelihood of benefit from EET (H/I subscore). We have previously shown that the use of BCI increases patient and physician confidence in decision-making and leads to fewer recommendations for EET. The current analysis extends our results to a larger sample size and presents a health economic analysis to assess the cost effectiveness of the use of BCI for EET decision-making. Methods: We developed a fact-based economic model to project the cost effectiveness of BCI using a cohort of 140 patients with stage I-III HRBC from Yale Cancer Center and University of Pittsburgh Medical Center who had completed ≥3.5 yrs of endocrine therapy and had undergone BCI testing in the context of this study. Physicians completed questionnaires to indicate their recommendations for EET before and after BCI results. Costs associated with EET, toxicity, follow-up, and metastatic recurrence were modeled over 5 yrs of extended therapy. Model inputs were based on published literature. Sensitivity analyses were performed around key inputs to estimate effects on the model. Results: Changes in EET recommendations after BCI were observed in 29% of patients, with 21% changing from recommended to not recommended, and 8% from not recommended to recommended. The projected net cost savings of BCI testing in this population of patients who are disease free at 5 yrs post-diagnosis is $5,190 per patient tested. Gross cost savings were projected to be achieved through reduced recurrence in patients receiving EET based on BCI results and decreased adverse events and comorbidities for patients with low BCI scores who did not receive EET. Conclusions: Based on the decision impact of BCI in a real-world cohort, the test is projected to be cost saving for women with early stage hormone receptor positive breast cancer who are recurrence free at 5 yrs post-diagnosis on adjuvant endocrine therapy.