Lacking health insurance coverage may be a leading driver for racial disparities in breast cancer detection and mortality rates, according to a new study.
The study, published Thursday in JAMA Oncology, marks one of the first examinations of how insurance has contributed to later diagnosis of breast cancer among women in ethnic minorities and resulted in poorer disease outcomes.
Nearly half of the minority women diagnosed with late-stage breast cancer were uninsured or on Medicaid, according to the results.
"Inadequate health insurance coverage also mediates the growing survivorship gap experienced by racial and ethnic minorities with cancer," said study co-lead author Dr. Naomi Ko, director of inpatient medical operation and assistant professor of medicine at Boston University School of Medicine.
More than 177,000 women age 40 to 64 who were diagnosed with stage 1 to 3 breast cancer between 2010 and 2016 were included in the study, which used data from the National Cancer Institute's surveillance, epidemiology, and end results, or SEER, program.
The study found 89% of white women were insured at the time of diagnosis compared with 74% of black women, 57% of American Indian-Alaska Native women, 82% of Asian women and 66% of Hispanic women.
A larger proportion of minority women were diagnosed at later stages of breast cancer compared to white women. Seventeen percent of black women and 16% of Hispanic women were diagnosed at stage 3 of the disease, when the five-year survival rate is estimated at 72%. Only 11% of white women were diagnosed at stage 3.
By contrast, 54% of white women were diagnosed with stage 1 breast cancer, which has a five-year survival rate of 100%. By contrast, 41% of black women and 43% of Hispanic women caught their breast cancer at stage 1.
Patients diagnosed with a later stage of breast cancer typically require more intensive treatment and are at a higher mortality risk, according to Ko.
"Insurance is a modifiable risk factor and having adequate health insurance for all could reduce the persistent racial outcome disparities in breast cancer," Ko said.
The breast cancer death rate is 40% higher among black women than white women, even though black women have a lower incidence rate, according to figures from the American Cancer Society. The disparity is more significant among black women under age 50, who die from the disease at double the rate of white women.
Later detection and higher mortality rates in women of racial minorities has been linked to risk factors like difficult accessing healthcare services and inadequate insurance coverage for years. The study hoped to quantify the association between insurance status and the risk of more advanced stages of cancer in racial minorities.
Dr. Stephanie Bernik, chief of breast surgery at Mount Sinai West Hospital in New York, expressed concern that the study's emphasis on insurance could ignore other underlying issues that lead to the disparities.
"People shouldn't simplify it too much and just say it's a matter of insurance," Bernik said. "The problem is much more complicated and much more intertwined to a patient's whole life cycle, which includes genetics, environment and lack of care and access — it's not a mathematical formula."