TOPLINE:
Women with BCI HOXB13/IL17BR ratio (BCI[H/I])–low tumors showed significant benefit from OFS, whereas those with BCI(H/I)-high tumors did not.
METHODOLOGY:
- Researchers conducted a prospective-retrospective translational study using tumor tissue samples from 1,718 premenopausal women with hormone receptor–positive early-stage breast cancer.
- Participants were randomly assigned to receive 5 years of tamoxifen alone, tamoxifen plus OFS, or exemestane plus OFS.
- BCI testing was performed on RNA extracted from formalin-fixed paraffin-embedded tumor specimens, blinded to clinical data and outcomes.
- The primary endpoints were breast cancer–free interval (BCFI) and distant recurrence-free interval (DRFI), with a median follow-up time of 12 years.
- Settings spanned multiple centers internationally, and data were collected from December 2003 to April 2021, analyzed from May 2022 to October 2022.
TAKEAWAY:
- According to the authors, patients with BCI(H/I)-low tumors exhibited a 12-year absolute benefit in BCFI of 11.6% from exemestane plus OFS (hazard ratio [HR], 0.48; 95% CI, 0.33-0.71) and 7.3% from tamoxifen plus OFS (HR, 0.69; 95% CI, 0.48-0.97), relative to tamoxifen alone.
- Patients with BCI(H/I)-high tumors did not derive significant benefit from either exemestane plus OFS (absolute benefit, -0.4%; HR, 1.03; 95% CI, 0.70-1.53) or tamoxifen plus OFS (absolute benefit, -1.2%; HR, 1.05; 95% CI, 0.72-1.54), compared with tamoxifen alone.
- In the ERBB2-negative subgroup, patients with BCI(H/I)-low tumors experienced a 12-year absolute benefit of 13.2% in BCFI from exemestane plus OFS (HR, 0.39; 95% CI, 0.25-0.60) and 7.4% from tamoxifen plus OFS (HR, 0.64; 95% CI, 0.44-0.93), compared with tamoxifen alone.
- BCI continuous index was significantly prognostic in the subgroup for DRFI (n = 1110; P =.004), with 12-year DRFI of 95.9%, 90.8%, and 86.3% in BCI low-risk, intermediate-risk, and high-risk cases of cancer than had not spread to nearly lymph nodes (N0 cancers), respectively.
IN PRACTICE:
“This investigation suggests a potential clinical use of BCI(H/I) results, adding to their use to identify patients most likely to benefit from extended endocrine therapy, as proven in multiple studies, although in the extended endocrine validation studies, it was the BCI(H/I)-high group that derived the greatest benefit,” wrote the authors of the study.
SOURCE:
The study was led by Ruth M. O’Regan, MD, University of Rochester Department of Medicine in Rochester, New York. It was published online on August 15, in JAMA Oncology.
LIMITATIONS:
The study’s retrospective nature may introduce biases despite the prospective statistical analysis plan. The sample size for certain clinical subgroups might be too small to definitively confirm the predictive value of BCI(H/I) for OFS benefit. The generalizability of the findings may be limited due to the specific population studied. Further validation in other patient cohorts is necessary to confirm these findings.
DISCLOSURES:
Dr. O’Regan disclosed receiving personal fees from Pfizer and Gilead DSMB, grants from Puma, and nonfinancial support from Novartis. Additional disclosures are noted in the original article.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.