Why Cancer in One Breast May Affect the Other

Researchers identify certain factors that seem to increase risk

MONDAY, Jan. 26 (HealthDay News) -- Researchers say they have found a way to better calculate the risk a woman with cancer in one breast has of developing tumors in the other breast.

The chances of developing cancer in a second breast, known as contralateral breast cancer, increases once a tumor has been found in one breast. And certain factors, such as a family history of breast cancer, further increase this risk, prompting some women to opt for preventative surgery.

However, there are no foolproof predictors.

But in a study by researchers at the University of Texas M.D. Anderson Cancer Center in Houston, three independent risk factors were found in women who had cancer in both breasts:

• Having cancer cells with certain invasive characteristics.
• Having cancer in more than one quadrant of the breast.
• Having a five-year risk of 1.67 percent or greater on a standardized breast cancer risk assessment tool that's based on what is known as the "Gail model." Designed for women without breast cancer, the model incorporates a woman's medical history, age, race and other characteristics.

The study, published in the March 1 issue of Cancer, also found a greater risk for women who are initially diagnosed with breast cancer at age 50 or older or who have additional moderate- to high-risk cells in their affected breast.

More information

The U.S. National Cancer Institute has more about breast cancer.
-- Kevin McKeever

SOURCE: American Cancer Society, news release, Jan. 26, 2009

Last Updated: Jan. 26, 2009

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