Age to initiate breast cancer screening should be adjusted for ethnicity

Women's breast cancer mortality rates differ significantly based on their ethnic ancestry. For example, black U.S. women have a 40 percent higher risk of dying from breast cancer than white women - with a nearly identical incidence rate. The difference is even more dramatic in younger patients under the age of 50: In this age group, breast cancer mortality is actually twice as high among black women as among white women. Contributing to the higher breast cancer mortality rates among black women may be health care disparities, but also the higher proportion of aggressive subtypes of breast cancer, as well as several social factors.

"Unfortunately, despite these enormous differences, no screening recommendations have been derived to date that are adjusted to the individual risks depending on the ethnic descent," says, Mahdi Fallah, who conducts research at the German Cancer Research Center and NCT Heidelberg.

In order to be able to put such recommendations on a statistically sound basis, Fallah's team of researchers have now analyzed data on the more than 415,000 U.S. women who died of breast cancer between 2011 and 2020. These data were collected by the National Center of Health Statistics and fully cover the U.S. population.

Among women younger than 50 years, breast cancer-specific mortality varied significantly depending on their ethnic ancestry. For example, black women aged 40 to 49 experienced 27 breast cancer deaths per 100,000 person-years, white women experienced 15, and women of Asian or Pacific Islander ancestry experienced only 11 (US total: 15).

The Heidelberg epidemiologists calculated the average risk of dying from breast cancer for U.S. women in different age groups. For example, the total U.S. female population at age 50 has a mean 10-year cumulative risk of dying from breast cancer of 0.329 percent. Women from different ethnic groups reached this risk threshold at different ages: black women ready at age 42, white women at age 51, and Asian or Pacific Islander women not until age 61.

At age 45, U.S. average women have a median 10-year risk of 0.235 percent. Black women reach this risk threshold at age 38, white women at age 46, and Asian and Pacific Islander women at age 50.

At age 40, the 10-year risk of death from breast cancer for all U.S. women is 0.154 percent. Black women reach this risk threshold at age 34, white women at age 41, and Asian or Pacific Islander women at age 43.

Another finding of the study: even before age 50, black women have higher breast cancer mortality compared with white U.S. women. Age 50 is the usual age of entry for breast cancer screening in the United States. "Thus, the substantial difference in mortality between black and white U.S. women cannot be attributed solely to unequal access to screening," explains study leader Fallah.

Fallah adds: "Our findings suggest that the age for initiation of breast cancer screening in the U.S. should be adjusted based on ethnicity so that all women can benefit equally from screening. And it would be important to conduct comparable studies in the European population to examine whether women with a certain migration background could benefit from different screening recommendations."

„Screening according to a 'one size fits all' scheme disadvantages women from certain ethnic groups. Other women, on the other hand, may take up breast cancer screening unnecessarily early and thus may be more likely to experience their adverse side effects, such as false-positive tests or overdiagnosis. With the results of our studies, we can now make evidence-based recommendations for starting breast cancer screening that are adjusted for ethnic ancestry, " Fallah says.

Tianhui Chen, Elham Kharazmi, Mahdi Fallah: Race and Ethnicity–Adjusted Age Recommendation for Initiating Breast Cancer Screening
JAMA Open network 2023, DOI: 10.1001/jamanetworkopen.2023.8893