Study: Number of Relatives With Breast Cancer Key Indicator of Risk

Number of first-degree relatives who have breast cancer appears to be an important indicator of a woman's risk of getting the disease, according to researchers at Oxford.

In their report published in The Lancet, researchers said that first-degree relatives of women with breast cancer are at an increased risk of developing the disease and the more affected relatives a woman has, the more likely she is to develop breast cancer.

Researchers with the International Collaborative Group on Hormonal Factors in Breast Cancer combined the results of 52 studies already completed and compared the prevalance of breast cancer in first-degree relatives of more than 58,000 women with breast cancer with prevalance in almost 102,000 women without breast cancer.

The lifetime incidence of breast cancer for women with one affected relative was 7.8 percent; for women with two affected relatives 3.3 percent; and for women with three affected relatives 21.1 percent.

The risk was the same whether mother or daughter were affected, and the risks were greater in older women than younger women, according to the researchers.

Other Sources: The Lancet