In counties with poor land quality, particularly urban counties, there was a higher incidence of early-stage disease and total breast cancer.
A significant association has been found between poor environmental quality and breast cancer incidence, according to new research published in the journal Scientific Reports. The association was particularly strong in urban areas.1
Breast cancer is the most common cancer in women in the United States and is the second most lethal invasive cancer. Previous studies have demonstrated a link between breast cancer and the environment, but most have only focused on single or small classes of specific contaminants.
“Individual environmental contaminants have long been associated with breast cancer, but we have limited understanding of how multiple exposures simultaneously affect this disease,” said senior author Gayathri Devi in a release.2 “Our study explored the incidence of breast cancer within the context of the Environmental Quality Index (EQI)—a county-by-county assessment of air, water, land, built environment, as well as the sociodemographic environment.”
Investigators from Duke University Medical Center conducted a study to analyze incidence rates of total, in situ, localized, regional, and distant breast cancers by rural-urban status. Data for the study was gathered from the North Carolina Central Cancer Registry, a reporting system for all cancer diagnoses of residents in the state. Breast cancer cases diagnosed from 2010 through 2014 were the focus of the study.
Investigators found that the total incidence rate for breast cancer was 153.5 cases per 100000 residents. The majority of cases were localized (54%), followed by regional (26%), in situ (16%), and distant (4%). The northeastern region of the state was seen to have the highest incidence rate of all breast cancer stages, while the central region had the highest incidence of in situ.
Total breast cancer incidence was higher by 10.82 cases per 100000 residents in areas that had poorer environmental quality, with a strong association for localized breast cancer. In counties with poor land quality, particularly urban counties, there was a higher incidence of early-stage disease and total breast cancer.
Additionally, sociodemographic and water environmental quality did not have significant associations with breast cancer incidence for any summary stage.
“Our analyses indicate significant associations between environmental quality and breast cancer incidence, which differ by breast cancer stage and urbanicity, identifying a critical need to assess cumulative environmental exposures in the context of cancer stage,” Larisa M. Gearhart-Serna, lead author on the study, said in a release.2 “This has the potential to develop measures to reduce disease incidence in vulnerable communities.”