Rates of breast cancer locoregional recurrence are almost two times higher in Black and Asian women compared with White women, even when patients have equal access to care and equivalent rates of treatment adherence, a recent analysis found.
After adjusting for patient demographics, clinical features, and treatment factors, the analysis suggested that “Asian race and Black race were independently associated with locoregional recurrence” among those with HR-positive, ERBB2-negative, early-stage breast cancer, the authors write in their analysis, published last week in JAMA Surgery.
Asian and Black race were also associated with the highest rates of locoregional recurrence following mastectomy and for those with a recurrence score of 11 or greater, despite similar tumor and treatment characteristics across racial and ethnic groups, the authors reported.
Commenting on the study in an accompanying editorial, Lisa A Newman, MD, MPH, noted that “these data are groundbreaking because of their inherent value in documenting disparities.”
“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,” said Newman, of Breast Surgical Oncology, in the Department of Surgery at Weill Cornell Medicine in New York City.
Although previous findings from the prospective randomized TAILORx trial revealed worse survival among Black patients, the current post hoc analysis is the first to show racial and ethnic differences in locoregional recurrence, the authors explained.
The TAILORx trial randomly assigned women with T1-2N0 HR-positive, ERBB2-negative breast cancer based on their Oncotype DX recurrence score to treatment with endocrine therapy alone (recurrence score <11), endocrine therapy alone vs chemotherapy followed by endocrine therapy (recurrence score 11-25), or chemotherapy followed by endocrine therapy (recurrence score >25).
The post hoc analysis included 9369 patients, of whom 4.6% were Asian, 9.4% Hispanic, 7.2% Black and 78.8% White.
Overall, the authors reported high rates of treatment acceptance, with only 9.3% crossover of treatment groups, as well as high rates of treatment receipt and duration across racial and ethnic groups, with the median duration of endocrine therapy lasting more than 60 months. Most patients (72.6%) received radiation, including 96.1% after breast-conserving surgery and 13% after mastectomy.
With a median follow-up of 94.8 months (range, 1-138 months), the 8-year rates of locoregional recurrence were highest among Black patients (3.9%), followed by Asian patients (3.6%), Hispanic patients (3.1%), and White patients (1.8%) (P < .001).
After adjusting for patient, tumor, and treatment characteristics, Asian and Black race were independently associated with a risk of locoregional recurrence (hazard ratio [HR], 1.91 and 1.78, respectively).
When stratifying patients by surgery type, Asian and Black race had a nearly threefold higher rate of locoregional recurrence following mastectomy compared with White women (6.3% and 6.5%, respectively, vs 2.4%; P = .009).
Among patients with recurrence scores of 11 to 25, Black patients had the highest probability of 8-year locoregional recurrence compared with White patients (5.1% vs 1.8%; P < .001). And among those with recurrence scores greater than 25, Asian patients had the highest locoregional recurrence rate (10.6% vs 3.0%; P = .026).
Locoregional recurrence was independently associated with a nearly sixfold increased risk of breast cancer mortality (HR, 5.71). But compared with White patients, Asian and Black patients did not have a statistically different risk of breast cancer mortality (HR, 0.81; 95% CI, 0.33 – 1.99 for Asian patients and HR, 1.50; CI 95% CI, 0.93 – 2.42 for Black patients). Hispanic patients, however, had a significantly lower risk for breast cancer mortality (HR, 0.21).
Other factors associated with locoregional recurrence included age younger than 50 years (HR, 1.78), higher tumor grade (HR, 2.21 for grade 3), and higher recurrence score category (HR, 2.77 for score >25).
Treatment factors, such as endocrine therapy and radiation therapy, were not associated with locoregional recurrence, whereas chemotherapy receipt was associated with a small decrease in locoregional recurrence (HR, 0.71).
Although this analysis did not find a significant association between race/ethnicity and breast cancer mortality, population-based mortality rates have been shown to be as much as 40% higher for Black women compared with White women in the US.
The authors explained that the increased locoregional recurrence among Black patients reported in this analysis may be “a possible contributor toward disparate breast cancer mortality in the US population.”
The racial and ethnic differences among a population with equal access to care suggests that “disparities in locoregional recurrence in the general population might be even wider when considering broader disparities in access, timeliness, and adherence to treatment outside of a clinical trial,” the authors said.
Several study authors reported receiving speaking honoraria and consulting fees from pharmaceutical companies (the full list can be found in the original article). Newman reported receiving funding from the Susan G. Komen Breast Cancer Foundation, the Fashion Footwear Association of New York, and the Breast Cancer Research Foundation.
JAMA Surgery. Published online April 12, 2023. Abstract, Editorial
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