Differences in insurance account for more than one third of the increased mortality risk seen in black women with early-stage hormone receptor-positive breast cancer in comparison with white women who have the same disease, a national cohort study of women indicates.
That makes insurance a greater source of disparity between the two groups than tumor characteristics.
"Where there is equal treatment in clinical trials, for example, outcomes [between black and white patients] are equal not only for breast cancer but for colorectal and many other types of cancer," lead author Ahmedin Jemal, DVM, PhD, vice president of surveillance and health services research, American Cancer Society, Atlanta, Georgia, told Medscape Medical News.
"So I do believe that if we were able to equalize access to care, there would be a substantial reduction in the survival difference between black and white women, because lack of insurance is a major barrier for accessing both prevention and treatment services," he added.
The study was published online October 16 in the Journal of Clinical Oncology.
Investigators from the American Cancer Society, Emory University, in Atlanta, Georgia, and the Dana-Farber Cancer Institute, Boston, Massachusetts, analyzed data from the National Cancer Data Base. They identified women aged 18 to 64 years who had been diagnosed with stage I to III breast cancer from 2004 to 2014.
There were 484,760 white women and 78,737 black women in the study.
"The median follow-up time from date of diagnosis was 4.9 years," the investigators write.
After matching the participants with respect to age, year of diagnosis, and place of residence, the excess mortality risk among black women with hormone receptor–positive breast cancer was 105.1% compared with white women (hazard ratio [HR], 2.05).
When the women were matched by demographics and the presence of comorbidities, the excess mortality risk decreased to 93.2% (HR, 1.93).
Matched for demographics, comorbidities, and insurance coverage, the excess mortality risk dropped to 29.9% (HR, 1.30).
When black and white women were matched for demographics, comorbidities, insurance coverage, tumor characteristics, and treatment, the excess mortality risk narrowed to 24.9% (HR, 1.25).
The investigators determined that differences in insurance coverage accounted for 37% of the excess mortality risk between the two groups with early-stage, hormone receptor-positive disease. Tumor characteristics accounted for 23.2% of the excess risk.
Differences in comorbidities accounted for 11.3% of the excess mortality risk between black and white women. Differences in treatment accounted for 4.8% of the excess mortality risk between the two groups.
The excess mortality risk between black and white women with hormone receptor-negative breast cancer was smaller, the study authors point out.
When matched for demographics, there was a 49.5% excess mortality risk among black women with hormone receptor–negative breast cancer compared to white women (HR, 1.50).
This excess mortality risk again dropped in a step-down fashion when women were sequentially matched for demographics, the presence of comorbidities, insurance coverage, tumor characteristics, and treatment.
However, here again, insurance coverage accounted for more than one third of the total excess mortality risk between black and white women, at 34.1%, followed by tumor characteristics (22%), comorbidities (3.8%), and treatment (3.6%).
Insurance Coverage
Asked to explain why insurance coverage plays such a pivotal role in the excess mortality risk between black and white women with early breast cancer, Dr Jemal pointed out that in the study, black women were more likely to have either no insurance or inadequate insurance, in the form of Medicaid, compared to white women (22.7% vs 8.4%).
Black women were also significantly more likely than white women to have hormone receptor-negative cancer, at 35.2% vs 19.3%.
They were also almost twice as likely to have larger and higher-grade tumors at the time of presentation, as well as stage II or III breast cancer, than white women (P < .001 for all comparisons).
"What's happening here is that patients were retroactively enrolled in Medicaid after their diagnosis of breast cancer," Dr Jemal explained.
"And to get approval for Medicaid, you have to show income, assets, a lot of things, so it takes time to initiate treatment, because without insurance in the US, good luck with accessing care," he added.
This delay in the initiation of treatment very likely explains why black women present with larger, later-stage, higher-grade tumors, Dr Jemal suggested.
Indeed, in an earlier study, investigators found that the delivery of adjuvant chemotherapy was significantly delayed for both black and Hispanic women following surgery for breast cancer compared with white women.
"It's very troubling, very disturbing, but we can't stop talking about these racial disparities," Dr Jemal said.
"Though it will be a challenge, it's my hope that things will change for the good in the future," he added.
One Study Where Care Trumped Race
Asked by Medscape Medical News to comment on the study, Quyen Chu, MD, director of surgical oncology at the Feist-Weiller Cancer Center in Shreveport, Louisiana, noted that he and his colleagues found that when black and white women have equal access to high-quality care, their outcomes are virtually identical.
In Dr Chu's and colleagues' study, both black and white women lived in areas of Louisiana where the median annual income in 2009 was $16,594, indicating that black and white women had similar, albeit low, socioeconomic status.
A significant proportion of patients in the study also had only Medicaid coverage.
Overall survival at 5 years was 81% for black women and 84% for white women; recurrence rates were similar for the two groups.
"Despite African-American women having larger tumor size and more triple-negative breast cancer than white women, outcomes were similar," Dr Chu said in an email.
"This suggests that irrespective of differences in tumor biology, we are still able to mitigate these differences when we provide equal access and treatment for all," he noted. He also indicated that in his study, the results achieved for both black and white women were comparable with the national average, stage for stage.
Until the early 1980s, mortality from breast cancer was in fact higher in white women than in black women.
However, in 2014, all-cause mortality rates following a diagnosis of breast cancer were 41% higher in black women than in white women. In part, that is a reflection of the fact that white women have benefited more than black women from the many advances in diagnosis and treatment of breast cancer that have been made since then.
Dr Jemal and Dr Chu have disclosed no relevant financial relationships.
J Clin Oncol. Published online October 16, 2017. Abstract
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Cite this: A Black, White Mortality Gap Much Explained by Insurance - Medscape - Oct 19, 2017.
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