Breast Cancer Clusters May Start in Childhood

By Cat Lazaroff

BUFFALO, New York, June 26, 2002 (ENS) - Researchers seeking the environmental triggers of breast cancer may need to look far back into a woman's past, suggests a novel study by geographers and epidemiologists at the University at Buffalo (UB). Where a woman lives at birth and puberty may have an impact on her risk of developing breast cancer later, the team concluded.

The researchers compared residential history data provided by women with breast cancer and a control group without cancer in western New York. Using geographic positioning technology, the researchers showed that the women who developed breast cancer were more likely to have lived closer together at birth and at their first menstruation - a concept called clustering - than women who did not develop breast cancer.

The findings indicate that there may be something in the environment close to these clusters that influences a woman's breast cancer risk, said Dr. Jo Freudenheim, professor in the department of social and preventive medicine in the UB School of Medicine and Biomedical Sciences, and senior author on the study.

A woman performs a self examination looking for changes that may indicate breast cancer. (Photo courtesy Columbia University)

"Not too long ago, researchers were looking only at relatively recent environmental exposure, maybe in the last 10 years, when we were studying the relationship of environment to breast cancer risk," Freudenheim said.

"Recently we've come to understand that breast cancer risk may be influenced by events early in life. These data support that hypothesis," said Freudenheim. "The next step is to identify where these places are and see if we can identify exposures that explain the clusters."

Freudenheim is principal investigator on a three year project funded by the U.S. Department of Defense to study the possible link between breast cancer and early environmental exposure to potential carcinogens. Some of the first findings of that research were presented June 21 at the annual meeting of the Society for Epidemiological Research.

The project piggybacks on Freudenheim's ongoing case control study of breast cancer in Erie and Niagara counties in Western New York, which involves 1,170 women with breast cancer and 2,116 healthy women. Of this total, 1,073 women who were born in either of the two counties and had provided the address of their residence at birth became the focus of the current research.

UB geographers and epidemiologists are entering residential data into a computerized mapping program, along with the location of steel mills, chemical factories, gasoline stations, toxic waste sites and other industrial sites in existence in the two counties between 1918-80.

They then will calculate the distance between these sites and the women's homes at the time of birth and menarche - the date of their first menstruation - and compare this information for the participants with and without cancer.

These early data revealed the greatest clustering of cancer cases at the time of menarche, said Daikwon Han, a graduate student in geography who is first author on the study. Some clustering also was evident for place of birth, he said, but there was no clustering effect for the women at the time they first gave birth

The biomedical research building at the University of Buffalo. (Photo courtesy UB)

One out of every eight women in the United States will develop breast cancer, cancer experts say. Worldwide, 600,000 cases of breast cancer are diagnosed each year.

Breast cancer is the second leading cause of death in women.

The current research was supported by a grant from the Department of Defense Breast Cancer Research Program and from the National Institutes of Health.