The Disproportionate Impact of Breast Cancer Recurrence on Black and Asian Women

The likelihood of locoregional recurrence in early-stage, hormone-receptor-positive, HER2-negative, and node-negative breast cancer in Black and Asian women was approximately twice that of white women.

According to the researchers, the findings of the unplanned post hoc analysis of the TAILORx trial, which were published in the journal JAMA Surgery, indicate that additional research is required to better comprehend whether failure to rescue after locoregional recurrence contributes to racial disparities in breast cancer mortality.

Rationale and methodology

Olga Kantor, MD, MS, a researcher in the division of breast surgery at Brigham and Women’s Hospital and Dana-Farber Brigham Cancer Center, told Healio, “We wanted to provide a better understanding of why racial differences in breast cancer mortality are prevalent and not fully explained by known factors. Patterns of locoregional recurrence by race and ethnicity are not well defined, and we were interested in exploring if locoregional recurrence differences exist in the context of a clinical trial population with similar access to care and treatment.”

Kantor and colleagues looked back at 9,369 women with T1-2N0 hormone receptor-positive, HER2-negative, node-negative breast cancer who participated in TAILORx between 2006 and 2010. These women were 78.8 percent white, 9.4 percent Hispanic, 7.2 percent Black, and 4.6 percent Asian. In light of their Oncotype DX (Definite Sciences) repeat score, ladies in the preliminary had been arbitrarily appointed to get endocrine treatment alone, endocrine treatment versus chemotherapy followed by endocrine treatment or chemotherapy followed by endocrine treatment.

Stratified by race and ethnicity, the researchers defined locoregional recurrence as ipsilateral breast, skin, chest wall, or regional nodal recurrence without concurrent distant recurrence. They utilized unadjusted Kaplan-Meier and adjusted Cox proportional hazards regression models for survival analyses.

The median follow-up time was 94.8 months.

Findings

6,474 and 344 patients, respectively, underwent radiation treatment following breast-conserving surgery.

Results showed 8-year locoregional recurrence rates of 3.6% (95% CI, 1.6-5.6) among Asian women, 3.9% (95% CI, 2.2-5.4) among Black women, 3.1% (95% CI, 1.7-4.5) among Hispanic women and 1.8% (95% CI, 1.5-2.3) among white women (P < .001).

Survival analyses adapted to patient, tumor and treatment characteristics uncovered independent relationship between locoregional recurrence and Asian (HR = 1.91, 95% CI, 1.12-3.29) and Black race (HR = 1.78, 95% CI, 1.15-2.77). Additionally, independent associations of locoregional recurrence with increased breast cancer mortality were found in adjusted survival analyses (HR = 5.71, 95% CI, 3.5-9.31).

Implications

According to Kantor’s statement to Healio, the findings suggest that factors other than access to care or treatments have an impact on the risk of locoregional recurrence and that distinct underlying tumor biology may be at play.

“Further, outside of a clinical trial population, these differences in locoregional recurrence may be quite wider than what we report in this study,” she said. “Next steps include analysis of other populations of patients with breast cancer, including triple-negative and HER2-positive breast cancer, as well as larger population-based work to validate these findings and further define differences in locoregional recurrence across breast cancer subtypes. Hopefully, defining these differences will lead to future interventions or optimizations in care to narrow these disparities in breast cancer locoregional recurrences.”

The inherent value of the information in documenting racial and ethnic differences makes the findings noteworthy, Lisa A. Newman, MD, MPH, head of the breast surgery section at New York-Presbyterian and Weill Cornell Medicine in New York, wrote in an editorial that went with the study.

“Of at least equal importance, they also represent a practice-changing approach to breast cancer research, where clinical trialists incorporate tumor genomics into the study of breast cancer disparities,” Newman wrote.