Authors: Nicholas Siu-Li, Ian Pagano, Jami Aya Fukui
Published: 2023-06-04
DOI: 10.1200/jco.2023.41.16_suppl.549
Source: Full article
549 Background: Patients with early-stage hormone receptor-positive (HR+) breast cancer have a good prognosis. Prior studies have shown that extending endocrine therapy beyond the first 5 years reduces the risk of late distant recurrence. The Breast Cancer Index (BCI) is a gene expression assay that provides both a prognostic risk of late distant recurrence in addition to a yes/no prediction of benefit from receiving extended endocrine therapy. To date, no studies have examined the relationship between race and BCI score. This study aims to investigate the interaction between race and BCI scores in women with early-stage HR+ breast cancer. Methods: We analyzed BCI scores, demographics, and tumor characteristics from 89 women diagnosed with early-stage HR+ breast cancer. Univariate logistic regression analysis was run using race, BCI recurrence risk, hormone status, tumor size, or tumor grade as predictor variables. BCI prediction of benefit was used as the outcome variable. Results: Compared to Caucasians, Native Hawaiians had significantly greater odds of having a BCI score predicting benefit from receiving extended endocrine therapy (OR = 7.00, p = 0.04). Additionally, there were significantly greater odds of having a score predicting benefit among those who had a recurrence risk of 5-10% (OR = 3.84, p = 0.04), or ≥10% (OR = 9.16, p < 0.001) compared to a recurrence risk < 5%. Conclusions: Our findings highlight the utility of characterizing differences in BCI predictive and prognostic scores by race among breast cancer patients with early-stage HR+ tumors. Notably, Native Hawaiian women had 7.0 times increased odds of having a score predicting benefit of extended endocrine therapy compared to Caucasians. This result is salient given the high incidence of breast cancer among Native Hawaiians. Though not statistically significant, our data also demonstrated Filipinos had increased odds of a score predicting benefit as well. Furthermore, our findings show a direct correlation between prognostic risk of late distant recurrence and predictive benefit of extended endocrine therapy with a higher odds ratio associated with higher recurrence risk. Our study shows notable differences in BCI findings when stratifying patients by race. However, our sample size is relatively small, and we lack sufficient data from patients representing other races such as Hispanic and Black. Future studies may expand the sample size and adjust for known breast cancer risk factors. The goal is to identify trends that may improve our usage of the BCI as a tool to effectively guide hormone therapy recommendations in patients with early-stage HR+ breast cancer. [Table: see text]