Type of Benign Breast Disease and Family History Influence Subsequent Risk

Type of Benign Breast Disease and Family History Influence Subsequent Risk of Breast Cancer

Among women with benign breast disease, subsequent risk of breast cancer varies by type of benign breast disease and by family history of breast cancer, according to a study in the New England Journal of Medicine.

Benign breast disease refers to several types of noncancerous changes in breast tissue. Benign breast disease is often categorized as nonproliferative (a category which includes breast cysts), proliferative without atypia (an overgrowth of cells in the breast without the presence of cells which look abnormal) and atypical hyperplasia (a condition with certain abnormal features). Women with proliferative breast disease without atypia and those with atypical hyperplasia have been found to be more likely to develop breast cancer than women without these conditions. The extent to which nonproliferative breast conditions increase the risk of breast cancer is still uncertain. It’s also unclear whether family history of breast cancer affects the likelihood that a woman with benign breast disease will develop breast cancer.

The study evaluated 9087 women who were diagnosed with benign breast disease at the Mayo Clinic between 1967 and 1991. Sixty-seven percent of the women had non-proliferative breast disease, 30 percent had proliferative breast disease without atypia and four percent had atypical hyperplasia. The women were followed for a median of 15 years after their diagnosis of benign breast disease. The researchers compared the number of breast cancers that developed among the women with benign breast disease to the number of breast cancers that would be expected to occur among women in the general population.

During follow-up, 707 of the 9087 women with benign breast disease were diagnosed with breast cancer; this is significantly more than the 453 breast cancers that would be expected to occur in the general population. Risk of breast cancer varied across the categories of benign breast disease. Compared to an expected five cases of breast cancer per 100 women in the general population, breast cancer occurred in six per 100 women with nonproliferative conditions, 10 per 100 women with proliferative conditions without atypia, and 19 per 100 women with atypia. Having a family history of breast cancer also increased the risk of breast cancer. Furthermore, among women with nonproliferative conditions, risk of breast cancer was increased only among women with a strong family history of breast cancer. Among women with other types of benign breast disease, risk of breast cancer was increased whether or not the woman had a family history of breast cancer.

The authors conclude that type of benign breast disease and family history of breast cancer play an important role in determining the breast cancer risk of a woman with benign breast disease.

References: Hartmann LC, Sellers TA, Frost MH et al. Benign breast disease and the risk of breast cancer. New England Journal of Medicine. 2005;353:229-237.

Accompanying editorial: Elmore JG and Gigerenzer G. Benign breast disease – the risks of communicating risk. New England Journal of Medicine. 2005;353:297-299.

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