Dr. Marc Lippman, deputy director of the University of Miami's Sylvester Cancer Center, said the majority of breast cancer risk is related to hormones.
s "Ninety percent of breast cancer risk is clearly related to differences in the hormone environments for women, either their own hormones or the hormones they take," he said. Exposure to hormones starts early in life at puberty, and adds up over time, he explained. Differences in risk can vary depending on the age of onset of puberty, for example.
Lippman said he didn't expect the findings to lead to any new recommendations for screening or treatment but said information about risk factors clearly linked to breast cancer, such as weight, have led him to encourage his patients to eat healthier diets and follow the other advice given in the report.
The authors hope their report leads research into a new direction, including a closer look at certain chemical exposures.
"[There is a need for] research on the etiology of breast cancer to do more to incorporate new understanding of breast development over the life course, recent advances in elucidating the molecular biology of tumorigenesis, and the challenges of assessing the potential impact of a multitude of low level chemical exposures."
Susan G. Komen for the Cure, the breast cancer advocacy group that funded the IOM research, said in a press release it hopes other agencies will join the research effort.
"We would like to issue a challenge to other agencies working in the environmental area to join with Susan G. Komen to create a fund to begin work on these very important initiatives," the group said.