The risk of a woman developing breast cancer may be significantly increased by her occupation, scientists working in the Windsor-Essex County area have found.
James Brophy and Margaret Keith, both of whom hold Ph.D.s in occupational and environmental health, have completed a two-year study of breast cancer patients.
The study involved 569 women with breast cancer from Essex and Kent counties who were patients at the Windsor Regional Cancer Centre and a control group of 600 cancer-free women in the same community. It looked at women’s occupations over their lifetime.
“We were attempting to address this huge gap in scientific information and knowledge, which is what is the occupational history of cancer patients, Brophy says.
“The study found that women with breast cancer had a significantly elevated risk if they ever had worked in agriculture compared with women who had not worked on farms,” says Brophy, executive director of the Occupational Health Clinics for Ontario Workers.
“The risk stayed the same or increased when those women moved to jobs in either the auto industry or in health care,” Brophy says.
“There is a lot of concern about young women being exposed to pesticides and other chemicals for a number of reasons,” Brophy says.
“The interesting thing for us was that women start farming as children, since virtually all children living on farms work on them. They start picking tomatoes, hoeing or de-tasselling corn and so on.”
“The reason for concern is that a younger person is at their most biologically active. Secondly, breast tissue, until the time of the first pregnancy, is what they call undifferentiated, and biologically, that means the breast tissue doesn’t really know its function until the first pregnancy.
“Those cells are particularly susceptible to carcinogens,” Brophy says. “And there’s an issue with hormonal disruption.”
Certain chemicals, pesticides, hydrocarbons, solvents, gasoline and plastics mimic the actions of estrogen in the body and have the potential to disrupt the hormonal system. There are about 200 substances that have been associated with breast cancer in animal studies.
“The known or suspected risk factors are almost all related to what is called estrogen load, lifetime estrogen exposure,” Brophy says. “And there is a whole host of substances that mimic the effect of estrogen. If you get exposed at a certain moment biologically, the impact can be profound.”
Health care workers may be at an increased risk for breast cancer because of exposures to environmental factors such as X-rays and chemicals that have been used as sterilizing agents, for example.
The results of the study will be published by the New York Academy of Science in mid-October.