Hologic's Breast Cancer Index Test Demonstrates Significant Impact on Extended Endocrine Therapy Decisions in Real-World Study
Key Insights
New data from the BCI Registry Study shows physician recommendations for extended endocrine therapy increased by more than 30% among patients identified as likely to benefit from the Breast Cancer Index Test (search).
Among patients identified as unlikely to benefit from extended therapy, physician recommendations decreased by nearly 40%, demonstrating the test's ability to guide personalized treatment decisions.
The Breast Cancer Index Test (search) is the only genomic assay with exclusive guideline recognition from NCCN (search) and ASCO (search) for extended endocrine therapy decision-making in hormone receptor-positive breast cancer.
Hologic and its subsidiary Biotheranostics (search) have announced new real-world evidence demonstrating how the Breast Cancer Index (BCI) Test significantly influences extended endocrine therapy decisions for patients with early-stage, hormone receptor-positive (HR+) breast cancer. The latest analysis from the ongoing BCI Registry Study reveals that physician recommendations for extended endocrine therapy increased by more than 30% among patients identified by the BCI Test as likely to benefit, while recommendations decreased by nearly 40% for those identified as unlikely to benefit.
Clinical Impact on Treatment Decisions
The BCI Registry Study data, to be presented at the 2026 ASCO (search) Annual Meeting on June 1, provides compelling evidence of the test's real-world clinical utility. The analysis shows dramatic shifts in physician decision-making patterns following BCI testing:
Overall Treatment Patterns:
- The percentage of patients recommended for extended endocrine therapy decreased from 54.6% before BCI testing to 41.2% after testing
- Conversely, the percentage of patients not recommended for extended therapy increased from 44.9% to 58% after testing
Among High-Benefit Patients (BCI H/I-High):
- Physician recommendations for extended endocrine therapy increased from 60.4% before testing to 90.6% after testing
Among Low-Benefit Patients (BCI H/I-Low):
- Recommendations decreased dramatically from 51.1% to 11.8%
Addressing Complex Treatment Decisions
"Decisions about extended endocrine therapy are complex, requiring physicians to balance recurrence risk, potential side effects, and clinical and pathologic factors," said Tara B. Sanft, M.D., of Hartford Healthcare (search) and lead author of the study. "Findings from the BCI Registry Study suggest that relying on those factors alone may not provide enough information for physicians and patients to make decisions with confidence."
The study highlights how genomic testing with the Breast Cancer Index Test (search) provides additional insight into tumor biology, helping physicians refine extended endocrine therapy recommendations and better identify which patients are most likely to benefit.
Established Clinical Guidelines Recognition
The BCI Test holds a unique position in breast cancer care as the established test for extended endocrine therapy decision-making, with exclusive guideline recognition from both the National Comprehensive Cancer Network (NCCN (search)) and the American Society of Clinical Oncology (ASCO (search)). Both organizations classify the BCI Test as the only genomic assay shown to predict who is likely to benefit from extended endocrine therapy beyond five years.
"Understanding who is likely to benefit from extended endocrine therapy is critical to personalizing care," said Sami Diab, M.D., Medical Director, Oncology at Hologic. "Findings from the BCI Registry Study continue to highlight the real-world impact of the Breast Cancer Index Test (search) in helping physicians make more informed treatment recommendations for their patients."
Test Characteristics and Clinical Application
The Breast Cancer Index Test (search) is a molecular, gene expression-based test designed to help physicians individualize treatment decisions for patients with early-stage, HR+ breast cancer. The test helps oncology care teams and patients navigate the difficult trade-offs between preventing disease recurrence and managing significant side effects and safety challenges related to unnecessary treatment.
The test has guideline designation from the American Joint Committee on Cancer for cancer staging based on molecular profile. It is performed as a sole-source laboratory-developed test (LDT) by Biotheranostics (search), Inc., a CLIA-certified and CAP-accredited diagnostic laboratory, though it has not been cleared or approved by the U.S. Food and Drug Administration.
The findings will be presented in detail at ASCO (search) 2026 on June 1, 2026, from 1:30-4:30 p.m. CDT as "Impact of the Breast Cancer Index on Extended Endocrine Therapy Recommendations in Patients from the BCI Registry Study" (Abstract #527/Poster Board #12 — Breast Cancer — Local/Regional/Adjuvant).