Racial Disparities Worsen Treatment Patterns and Adverse Events in Breast Cancer


In a study examining racial disparities, differences in curative intent, endocrine and/or chemotherapy, frequency and types of treatment-related adverse events, and more were seen in Non-Hispanic Black women vs Non-Hispanic White women with breast cancer.

Non-Hispanic Black women with breast cancer are less likely to undergo curative intent surgery or receive endocrine therapy than non-Hispanic White women. These racial groups also have a higher risk of cognitive decline or dementia after treatment for their cancer, according to new study results.

Findings from the study were published in Nature and emphasize the need for public policy measures to equalize access to quality healthcare for all patients in order to improve patient outcomes.

"Health disparities are a central topic nowadays. We already know that racial disparities exist in healthcare. This is also true for cancer patients. In this study, we analyzed specifically breast cancer patients. Evidence shows that women who are Black, have a higher incidence of the most aggressive subtype of breast cancer, are diagnosed at later TNM stages, and have higher rates of risk factors. Black women are over 40% more likely to die from breast cancer than White women. In addition, these patients have poorer access to healthcare, Nickolas Stabellini, , a part of the research team at University Hospitals Seidman Cancer Center, in Cleveland, Ohio and an MD/PhD candidate at Case Western Reserve University School of Medicine told Targeted OncologyTM.

In the study, investigators performed a comprehensive analysis to create a race-stratified epidemiological report which included the differences in treatment patterns and treatment related adverse events (AEs) for non-Hispanic women with breast cancer.

The goals of the trial were to assess treatment and time-to-treatment following index breast cancer diagnosis and determine the diagnosis and time-to-event of a treatment AE.

"We to these disparities fo Black women into consideration along with data from our institution, a tertiary cancer center that serves urban, suburban, and rural areas and that includes a higher percentage of Blacks than the overall United State population, evidence that non-Hispanic women with breast cancer are in fact diagnosed at later stages (probably reflecting poor screening), have a lower probability of undergoing breast cancer surgery or being prescribed endocrine therapy, have lower rates of appointments attended, are less likely to be diagnosed with psychological affections after cancer treatment (probably reflecting the poor access to health care and/or a poor relationship between patient and health care provider), and are more likely to be diagnosed with cognitive impairment after breast cancer treatment," Stabellini explained.

"This is important to show that the disparities, that start with healthcare access and screening, reflect on all the stages of healthcare, including treatment, treatment-related adverse events, and outcomes. As stated in our manuscript, our results point to the need for more personalized care and for public policies that equalize access to quality healthcare for minorities, Stabellini added."

A total of 17,454 women aged 18 years and older were included in the study if they were diagnosed with in-situ, early-stage, and late-stage breast cancer between 2005–2022. The median age of patients enrolled was 63 years (interquartile range [IQR] 53-73). Eighty-two percent were non-Hispanic White women, a majority of patients had a Charlson Comorbidity Score between 1 and 2 (68%), and TNM stage I (44.5%). In 51.5% of patients, surgery was performed, while 30.6% received radiotherapy, 26.4% received chemotherapy, 3.1% received immunotherapy, and 41.2% received endocrine therapy.

Eighteen percent of patients were non-Hispanic Blacks and were followed-up for a median of 4.4 years, as opposed to non-Hispanic Whites who were followed-up for a median of 8.1 years. non-Hispanic Black patients had a significantly higher probability of a prior smoking history at 13.5% vs. 9%, for non-Hispanic White patients (P< .001), ductal carcinoma (48.8% vs 39.9%; P < .001), and stage IV disease (6.4% vs 4.9%; P < .001).

Regarding racial disparities in treatment patterns between patients, Non-Hispanic Black vs White women had higher rates of surgery (58% vs 50.1%; P < .001), radiotherapy (42.1% vs 28%; P < .001), chemotherapy (34.6% vs 24.6%, P < .001), hormone therapy (42.6% vs 40.9%), immunotherapy (4.1% vs 2.8%, P < .001), and combined therapy.

These findings showed that non-Hispanic Black patients had a lower probability of undergoing surgery for their breast cancer (aHR = 0.92; 95% CI, 0.87-0.97) compared with non-Hispanic White women. non-Hispanic Black women also had a lower probability of being prescribed endocrine therapy (aHR = 0.83, 95% CI, 0.79-0.89), but a higher probability of receiving adjuvant radiotherapy (aHR = 1.40; 95% CI, 1.29-1.52).

There were longer delays for surgery for non-Hispanic Black patients at a median of 42 days (IQR 27-106) compared with 34 days (IQR 21-62), longer delays for radiotherapy at a median of 204 days (IQR 99-287) vs 138 days (77–253), chemotherapy at a median of 70 days (IQR 37–112) vs 62 days (IQR 39–95), and time to initiation of endocrine therapy at a median of 138 days (IQR 72-245) vs 126 days (IQR 72-218).

While non-Hispanic Black patients had a higher number of appointments per at 10 (IQR 5-23) compared with 8 (IQR 4-17) for non-Hispanic White patients, they also had lower median appointment completion rates at 66% appointments attended (IQR 44–80) vs 69% (IQR 50-85).

When evaluating treatment-related AEs in only patients who were given the respective treatments, non-Hispanic Black patients had higher rates of chemotherapy-related complications than White patients (20.9% vs 12.2%; P < .001). These AEs consisted of cardiomyopathy, diarrhea/enteritis, fatigue, nausea/vomiting, neuropathy, lung disease, pain, dehydration/hypovolemia, rash, and infusion reactions. There were also higher rates of cognitive decline/dementia for non-Hispanic Blacks vs Whites (13.6% vs 6.7%; P < .001).

There were no differences observed regarding the incidence of overall immune related toxicities (irAEs). However, higher rates cardiac toxicity acute myocardial infarction was seen for non-Hispanic Black vs White patients (3.1% vs 0.2%; P = .01), as well as pneumonitis (7.8% vs 2%; P = .003).

Additionally, non-Hispanic Black women had lower risk of being diagnosed with psychological issues (aHR = 0.71; 95% CI, 0.63-0.80) but a higher risk for cognitive decline or dementia (aHR = 1.30; 95% CI, 1.08-1.56).

"Our results reinforce that race is a social construct. These disparities exist because of racism and englobe the social determinants of health [SDOH]. Inequities in the SDOH factors impact the individual environments and the exposure to risk or protective factors. These inequities also generate stress, which is correlated with poor outcomes, including cardiovascular diseases. Therefore, our results, reinforcing the social construct of race, are showing that these inequities should be eliminated or attenuated, mainly by acting on the and adjusting our healthcare system to provide equitable care to everyone, independent of race, ethnicity, sex, or any other factor," said Stabellini. "Thus, the future of this space is to understand and quantify the role of each domain of the SDOH and what kind of actions can be done to achieve these desired outcomes. I add to this the idea that minorities should be more studied and more included. This is a movement that we are starting but we can improve."

Stabellini N, Cullen J, Cao L, et al. Racial disparities in breast cancer treatment patterns and treatment related adverse events. Sci Rep. 2023;13(1):1233. Published Jan 22, 2023. doi:10.1038/s41598-023-27578-4
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