• Posted November 22, 2023

Breast Cancer Rates Higher in Urban vs. Rural Areas

Environmental contaminants may be driving higher rates of breast cancer in urban areas compared to rural locales, a new North Carolina study finds.

"Our analyses indicate significant associations between environmental quality and breast cancer incidence," said lead author Larisa Gearhart-Serna, who led the research as a Ph.D. candidate at the Duke Cancer Institute in Durham, N.C.

The findings, published Nov. 20 in Scientific Reports, were based on data from the Environmental Quality Index (EQI) for North Carolina residents.

The EQI is "a county-by-county assessment of air, water, land, built environment, as well as the sociodemographic environment,"study senior author Gayathri Devi explained in a Duke news release. She's a professor of surgery and pathology and director of the Duke Consortium for Inflammatory Breast Cancer at the institute.

Devi and Gearhart-Serna compared EQI data against information on breast cancer case incidence (and cancer stage upon diagnosis) across North Carolina.

The team believe the state is a good model for disparities in breast cancer risk, with 10 million people spread across 100 rural and urban counties.

Some counties have better "environmental quality" than others, and the Duke team found that folks living in counties with poor environmental quality had about 11 more cases of breast cancer per 100,000 residents, compared to counties with good environmental quality.

That was especially true for cases of early (localized) breast cancer, they noted.

Urban counties with poor environmental quality were especially hard-hit by excess breast cancer cases. In some counties (both urban and rural), land contaminants such as pesticides, toxic chemicals from industry or agriculture appeared to play a role in cancer rates, the researchers said.

In North Carolina, black women appeared especially vulnerable. Counties with high percentages of black female residents had higher rates of late-stage breast cancer diagnoses, the study found. It's possible that lower rates of screening mammography might play a role in that disparity, the team said.

Gearhart-Serna said in the news release that the findings are crucial to "identifying a critical need to assess cumulative environmental exposures in the context of cancer stage. This has the potential to develop measures to reduce disease incidence in vulnerable communities."

More information

Find out more about breast cancer at the American Cancer Society.

SOURCE: Duke Health, news release, Nov. 20, 2023