Treatment Duration in Premenopausal Breast Cancer: The BCI Test (SABCS 2025)
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Treatment Duration in Premenopausal Breast Cancer: The BCI Test (SABCS 2025)
Extending endocrine therapy from 5 to 10 years or adding ovarian function suppression (OFST) is difficult in premenopausal ER+ early breast cancer. A major analysis of 11 studies presented at SABCS 2025 showed that the Breast Cancer Index (BCI) test outperforms 21-gene panels (RS) in predicting recurrence and personalizing treatment.
1) What Is BCI (Breast Cancer Index)?
BCI analyzes the HOXB13/IL17BR (H/I) gene ratio and molecular grade index in breast tumor tissue. It is the only FDA-approved test specifically identifying late recurrence risk after year 5 of endocrine treatment and who benefits from extended therapy.
2) Study Design (SABCS 2025)
In this Hologic/Biotheranostics-led analysis:
- Dataset: 11 studies, including SWOG S1007 and OPTIMA.
- Population: Premenopausal, ER+, HER2-negative, node-positive/negative.
- Aim: Compare 10-year distant recurrence-free survival (DRFS) by BCI score: Low <1.47 vs High ≥1.47.
3) 10-Year Distant Recurrence-Free Survival (DRFS)
By BCI ScoreData Interpretation
Low-BCI patients have a low 10-year recurrence risk (8%) and may be spared extended-treatment side effects. In the high-score group, recurrence risk reaches 25%; these patients benefit most from OFST and extended therapy.
4) Summary Data Table
| Parameter | Value / Result | Clinical Meaning |
|---|---|---|
| Predictive Power (HR) | 2.1 (p<0.001) | High BCI strongly predicts recurrence. |
| OFST Effect | 25% Risk Reduction | Significant only in the high-BCI group. |
| Comparison | BCI > 21-Gene RS | BCI is more sensitive than conventional tests in premenopausal patients. |
| Nodal Status | 10% Difference in Node-Positive Patients | Biology—genetics—determines risk even when lymph nodes are positive. |
Clinical Impact and Safety
BCI is a laboratory test without physical side effects. However, adverse effects of treatment decisions based on it—OFST + aromatase inhibitor—matter.
Potential Gains:
- De-escalation: Protects low-risk patients from unnecessary menopausal effects of OFST, such as hot flashes, osteoporosis, and sexual dysfunction.
- Optimization: Provides a scientific basis for intensive treatment to prevent early recurrence in high-risk patients.
Frequently Asked Questions
DROZDOGAN Academy Commentary
SABCS 2025 data indicate the end of uniform treatment for premenopausal women. Even with positive lymph nodes, genetically low-risk tumors may allow patients to avoid aggressive ovarian suppression's adverse effects. Decisions must be made with a physician.
References
- Ravdin P, Graham C, et al. SABCS 2025, Oral Session 4 (OS4-12). "Breast Cancer Index in premenopausal ER+ early breast cancer: Pooled analysis".
- Albain KS, et al. J Clin Oncol. 2017. (Original BCI Validation).
- Francis PA, et al. N Engl J Med. 2015 (SOFT/TEXT Studies).
Note: This content is based on SABCS 2025 congress presentation data and is informational, not medical advice.
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