Using data from the Surveillance, Epidemiology, and End Results (SEER) database, investigators conducted a population-based, retrospective cohort study to determine the magnitude of the differences in clinical treatment and outcomes between African American (AA) and white women with triple-negative breast cancer (TNBC)  and to determine what roles sociodemographic, clinical, and neighborhood factors play in TNBC outcome disparities. (TNBC is associated with higher rates of recurrences, metastases, and death within the first 5 years following diagnosis.) The SEER program provides information on cancer statistics in an effort to reduce the cancer burden among the U.S. population. SEER data were used to determine deaths that were attributed to BC.

Data on women who received a primary diagnosis of stage I to III TNBC (regardless of estrogen, progesterone, and ERBB2-receptor status) between 2010 and 2015, who were aged 18 years or older, and who reported their race to be AA or white were included in this analysis. The study sample included 23,213 patients, of whom one-quarter (5,881) were AA.

Among the variables studied were age at diagnosis, cancer stage, tumor size, lymph-node involvement, tumor grade, administration of cancer-directed treatment (i.e., surgery, chemotherapy, and/or radiation), neighborhood socioeconomic deprivation (based on information from the 2008-2021 American Community Survey), and rurality (based on classification by the U.S. Department of Agriculture).

The researchers found that AA patients were younger at diagnosis (age 56.3 years vs. 59.7 years); were more likely to be insured through Medicaid (20.6% vs. 8.8%), live in the most deprived counties (14.7% vs. 7.1%), and reside in urban counties (92.1% vs. 86.2%); had more pathologically aggressive stage III disease (20.3% vs. 15.2%), larger tumors (>5 cm: 14.3% vs. 9.6%), positive lymph nodes (39.0% vs. 31.6%), and more poorly differentiated/undifferentiated disease (81.5% vs. 76.0%); were 31% less likely to receive surgery (odds ratio [OR] = 0.69, CI: 0.60-0.79) and 11% less likely to receive chemotherapy (OR = 0.89, CI: 0.81-0.99); and had poorer 5-year specific BC survival rates (76.9% vs. 82.9%).  

The hazard ratio (HR) of BC mortality in AA patients was 1.28 compared with white patients, and this decreased to HR = 1.16 after clinicopathological and treatment factors were considered. When all of these factors were taken into account, AA patients had a higher risk of overall mortality (i.e., BC-specific and nonÐBC-related death).

When race-associated risk factors of BC mortality were examined further based on sociodemographic, neighborhood, and treatment factors, the risk of BC-related death was more common in younger AA patients (HR = 1.24, CI: 1.12-1.37) than in older AA patients (i.e., age > 65 years). Counterintuitively, for those living in less-socioeconomically-deprived counties, there was a 26% increased risk of BC-related death compared with those living in more deprived counties (HR = 1.26, CI: 1.14-1.39). Just as interestingly, AA patients who lived in rural areas had a 28% lower risk of death from BC than white patients who lived in rural areas (HR = 0.72, CI: 0.53-0.96).

When tumor stage was analyzed, there was a 19% excess risk of death from BC in AA patients with stage II BC who received chemotherapy (HR = 1.19, CI: 1.02-1.39) but not among AA patients with stage II BC who did not receive chemotherapy. The relationship between stage III BC and chemotherapy trended similarly to stage II BC for AA patients but did not reach significance, nor was there a significant correlation between stage I BC and chemotherapy.

The authors concluded that the risk of death from TNBC remained significantly elevated in AA women compared with white women after considering the role of demographics, health insurance, neighborhood, and clinicopathological and treatment factors.

Pharmacists should be alert to the risk of poor outcomes among AA women who are diagnosed with TNBC and should proactively promote the use of mammograms in this high-risk population.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

« Click here to return to Breast Cancer Update.