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Black women at higher risk for breast cancer recurrence, mortality
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SAN ANTONIO — Black women appeared to be at higher risk for breast cancer recurrence and overall mortality than white women, despite receiving similar treatment based on their 21-gene recurrence scores, according to results of the phase 3 TAILORx trial presented at San Antonio Breast Cancer Symposium.
“Our findings are consistent with prior studies indicating that black women with hormone receptor-positive, HER2-negative breast cancer have worse prognoses than women of other racial and ethnic backgrounds, even when they have access to the same contemporary cancer care,” Kathy Albain, MD, Huizenga family endowed chair in oncology research and professor of medicine at Loyola University Chicago Stritch School of Medicine, and director of the breast and thoracic oncology programs at Cardinal Bernardin Cancer Center of Loyola Medicine, said in a press release. “This suggests that additional research is required to determine the basis for these racial disparities and also highlights the need to enhance accrual of minority populations in cancer clinical trials.”
Albain and colleagues assessed clinicopathologic characteristics, treatment and clinical outcomes by race and ethnicity among 9,719 women with hormone receptor-positive, HER2-negative, axillary lymph node-negative, early-stage breast cancer who were included in the phase 3 TAILORx trial.
Regarding ethnicity, 79% were non-Hispanic, 9% were Hispanic and 12% were unknown. Regarding race, 84% were white, 7% black, 4% Asian, and 4% other or unknown race.
Researchers used the Oncotype DX Breast Recurrence Score test (Genomic Health) to assess patient tumor characteristics, with a risk score based on a scale of 0 to 100. Patients with low-risk tumors (0-10 risk score) received hormone therapy alone. Those with high-risk tumors (risk score 26) received hormone therapy plus chemotherapy, and those with intermediate-risk tumors (11-25 risk score) received hormone therapy plus chemotherapy or hormone therapy alone.
Results showed no significant differences in recurrence scores between black and white women, or in their median (17 vs. 17) or mean recurrence scores (19.1 vs. 18.2).
In addition, researchers noted similar usage and type of chemotherapy after surgery, and usage, type, and duration of hormone therapy, between black women and white women as well as between Hispanic and non-Hispanic women.
However, researchers observed a 39% (HR = 1.39; P = .02) higher risk for breast cancer recurrence and a 52% (HR = 1.52; P = .005) higher risk for mortality among black women vs. white women.
When the researchers analyzed separately for race and ethnicity, women who had intermediate recurrence scores (11 to 25) on the 21-gene test did not benefit from chemotherapy.
Among the population of women with an intermediate-risk score, black women had an 80% (HR = 1.8; P < .001) higher risk for recurrence and 67% (HR = 1.67; P = .003) higher risk for mortality than white women. Analysis among ethnic groups showed Hispanic women generally had better outcomes than non-Hispanic women.
“An important result of the study is that women of all races and ethnicities, when analyzed separately, could safely avoid chemotherapy if they had intermediate recurrence scores,” Albain said. “In addition, we found that the type and duration of chemotherapy and hormone therapy treatments were similar among black and white women and other races as well as between Hispanic and non-Hispanic women. Pathologic characteristics of the tumors were no different as well.”
Albain noted several limitations of the study, including the retrospective nature of the analysis, lack of adequate power to address specific questions in the race/ethnicity subsets, and a reliance on self-reported adherence to hormone therapy.
“The racial disparities observed in this trial were not explained by differences in recurrence score, duration or reported adherence to hormone therapy, nor were they explained by use of chemotherapy, or characteristics such as age, tumor size or tumor grade,” Albain said. “As such, our results suggest that biological differences may contribute to the significantly different outcomes of black women when compared with others with breast cancer.” – by Jennifer Southall
Reference:
Albain K, et al. Abstract GS4-07. Presented at: San Antonio Breast Cancer Symposium; Dec. 4-8, 2018; San Antonio.
Disclosures: The study was funded by the NCI and supported in part by the Breast Cancer Research Foundation, Susan G. Komen and the U.S. Postal Service Breast Cancer Research Stamp. Albain reports consultant/advisory committee roles for Agendia, Biotheranostics, Genentech/Roche, Genomic Health, Myriad, Novartis, Pfizer and Puma. Please see the abstract for all other authors’ relevant financial disclosures.