Examining a Genomic Test in Predicting Extended Endocrine Benefit and Recurrence Risk in a Diverse Breast Cancer Population
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Department of Medicine, John A. Burns School of Medicine, University of Hawai‘i, Honolulu, HI 96813, USA
2
Translational and Clinical Research, University of Hawaii Cancer Center, Honolulu, HI 96813, USA
*
Author to whom correspondence should be addressed.
Curr. Oncol. 2025, 32(10), 537; https://doi.org/10.3390/curroncol32100537
Submission received: 24 July 2025
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Revised: 4 September 2025
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Accepted: 24 September 2025
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Published: 25 September 2025
(This article belongs to the Section Breast Cancer)
Simple Summary
The Breast Cancer Index is a molecular test that helps providers decide if patients should continue hormone therapy after the standard first five years to reduce cancer recurrence. However, little is known about how race and ethnicity may influence the results of this test. In this study, we analyzed the Breast Cancer Index scores from 159 women with early-stage hormone receptor-positive breast cancer to assess racial and ethnic differences. Japanese and other Asian/Pacific Islander patients were less likely to be classified as high risk for recurrence compared with Caucasian patients. There were no major racial or ethnic differences in predicting who would benefit from extended hormone therapy, supporting the test’s applicability across diverse racial and ethnic populations. These findings suggest potential variations in tumor biology or other contributing factors, underscoring the need for further research.
Abstract
(1) Background: Extended endocrine therapy (EET) beyond five years can reduce distant recurrence in early-stage hormone receptor-positive (HR+) breast cancer. The Breast Cancer Index (BCI) predicts recurrence risk and EET benefits, yet racial/ethnic differences in its results remain unexplored. This study evaluates such differences in a diverse early-stage HR+ breast cancer population. (2) Methods: We retrospectively analyzed demographics, tumor characteristics and BCI scores of 159 women in Hawaii with early-stage HR+ breast cancer, self-identifying as Caucasian, Filipino, Japanese, Native Hawaiian, Other Asian/Pacific Islander, or Other. Tumor characteristics included size, grade, histology, lymph node/receptor status, Oncotype DX score, and laterality. Logistic regression used demographics and tumor features as predictor variables, with BCI’s benefit prediction and recurrence risk as outcome variables. (3) Results: Japanese and other Asian/Pacific Islander patients had significantly lower odds of high recurrence risk compared to Caucasian patients. Higher recurrence risk was associated with greater odds of predicted EET. Racial/ethnic differences in EET benefit prediction were not statistically significant. (4) Conclusions: No racial/ethnic differences in EET benefit prediction suggest BCI’s applicability in racially and ethnically diverse populations. Findings among Japanese and other Asian/Pacific Islanders point to potential biological or socioeconomic variation. Limitations include sample size and underrepresentation of certain groups. Future studies should address these gaps and adjust for known risk factors to further clarify BCI’s racial and ethnic implications.
