Women may be able to reduce breast cancer risk predicted by their genes

http://www.eurekalert.org/pub_releases/2016-05/jhub-wmb052416.php

Public Release: 26-May-2016
Women may be able to reduce breast cancer risk predicted by their genes
New model shows how healthy lifestyle choices can mitigate genetic, family history
Johns Hopkins University Bloomberg School of Public Health

Women with a high risk of developing breast cancer based on family history and genetic risk can still reduce the chance they will develop the disease in their lifetimes by following a healthy lifestyle, new research led by the Johns Hopkins Bloomberg School of Public Health suggests.

White women who are at high risk but who had a low body mass index (a marker for obesity), who did not drink or smoke and who did not use hormone replacement therapy, had roughly the same risk as an average white women in United States, the researchers found. The average chance that a 30-year-old, white woman will develop breast cancer before she is 80 is about 11 percent.

The researchers found that roughly 30 percent of breast cancer cases could be prevented by modifying known risk factors - say, by drinking less alcohol, losing weight and not taking hormone replacement therapy. More importantly, the study found that a larger fraction of total preventable cases would occur among women at higher levels because of genetic risk factors, family history and a few other factors that cannot be modified.

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"People think that their genetic risk for developing cancer is set in stone," says the study's senior author Nilanjan Chatterjee, PhD, a Bloomberg Distinguished Professor in the Department of Biostatistics at the Bloomberg School. "While you can't change your genes, this study tells us even people who are at high genetic risk can change their health outlook by making better lifestyle choices such as eating right, exercising and quitting smoking."

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The findings are currently applicable only to white women because further studies are needed to understand the association of the genetic variants with risk of breast cancer for other ethnic groups.

The common gene variations studied by the researchers are quite different from the well known rare mutations in genes like BRCA1 and BRCA2, where having a single variant can mean a very high risk of developing breast cancer.

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Chatterjee says he hopes that once women understand that their genes do not completely predict their cancer destiny, they will work even harder to make lifestyle changes that can potentially reduce the risk they will develop the deadly disease.

"Everyone should be doing the right things to stay healthy but motivating people is often hard," he says. "These findings may be able to help people better understand the benefits of a healthy lifestyle at a more individualized level."