In a population-based retrospective cohort study reported in JAMA Oncology, Cho et al found that Black women with nonmetastatic triple-negative breast cancer were less likely than White women to receive chemotherapy and surgery and were at higher risk of breast cancer mortality.
The study included SEER (Surveillance, Epidemiology, and End Results) data on 23,123 Black (n = 5,881) or White women (n = 17,332) who received a diagnosis of nonmetastatic triple-negative breast cancer between January 2010 and December 2015 and were followed through December 2016. Logistic regression analysis and competing risk regression analysis were used to estimate odds ratios of receipt of treatment and hazard ratios of breast cancer mortality in Black vs White patients.
In this retrospective cohort study, Black women with nonmetastatic triple-negative breast cancer had a significantly higher risk of breast cancer mortality compared with their White counterparts, which was partially explained by their disparities in receipt of surgery and chemotherapy.— Cho et al
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Compared with White women, Black women were younger at diagnosis (56.3 vs 59.7 years); more likely to be insured through Medicaid (20.6% vs 8.8%); more commonly lived in the most deprived counties (14.7% vs 7.1%) and in urban counties (92.1% vs 86.2%); and were more likely to have more aggressive disease, including stage III tumors (20.3% vs 15.2%), larger tumor size (> 5 cm in 14.3% vs 9.6%), positive lymph nodes (39.0% vs 31.6%), and poor differentiation/undifferentiated disease (81.5% vs 76.0%).
In analysis adjusting for sociodemographic, clinicopathologic, and county-level factors, Black women were less likely to receive surgery (odds ratio [OR] = 0.69, 95% confidence interval [CI] = 0.60–0.79) and chemotherapy (OR = 0.89, 95% CI = 0.81–0.99). No significant difference in receipt of radiation therapy was observed.
After a median follow-up of 43 months, 16.8% of Black patients and 13.2% of White patients had died of breast cancer. Cumulative breast cancer–specific survival at 5 years was 76.9% vs 82.9% (P < .001).
In analysis adjusting for sociodemographic and county-level factors, Black women had a hazard ratio for breast cancer mortality of 1.28 (95% CI = 1.18–1.38). After additional adjustment for clinicopathologic and treatment factors, the hazard ratio was 1.16 (95% CI = 1.06–1.25).
The increased mortality risk in Black patients was observed in women aged < 65 years (hazard ratio [HR] = 1.24, 95% CI = 1.12–1.37) but not in older women, those living in socioeconomically less deprived counties (HR = 1.26, 95% CI = 1.14–1.39) but not in more deprived counties, and those from urban areas (HR = 1.21, 95% CI = 1.11–1.32). Black women living in rural areas had a lower risk of death from breast cancer vs White women living in rural areas (HR = 0.72, 95% CI = 0.53–0.96).
Increased risk of mortality was observed among Black vs White patients with stage II disease who received chemotherapy (HR = 1.19, 95% CI = 1.02–1.39) but not in those who did not receive chemotherapy (HR = 0.90, 95% CI = 0.69–1.17). Increased risk was also observed among Black women with stage III disease who received chemotherapy (HR = 1.15, 95% CI = 1.01–1.31) but not among those who did not (HR = 0.97, 95% CI = 0.73–1.27).
The investigators concluded, "In this retrospective cohort study, Black women with nonmetastatic triple-negative breast cancer had a significantly higher risk of breast cancer mortality compared with their White counterparts, which was partially explained by their disparities in receipt of surgery and chemotherapy."
Ying Liu, MD, PhD, of Washington University in St. Louis, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by the National Cancer Institute, American Cancer Society, Breast Cancer Research Foundation, and Foundation for Barnes-Jewish Hospital. For full disclosures of the study authors, visit jamanetwork.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.