Women with a type of benign breast disease called atypical hyperplasia face a significant risk of developing breast cancer and should be screened frequently, a new study suggests.
The highest risk was found in pre-menopausal women with atypical hyperplasia who had a family history of breast cancer, according to today's Journal of the American Medical Association.
Atypical hyperplasia involves unusual but not cancerous changes in breast tissue. Cells in the breast tissue increase but don't form a tumor.
Unlike other forms of benign breast disease, which involve a non-cancerous lump, atypical hyperplasia often is found in non-lumpy tissue, said Dr. Stephanie London of the University of Southern California, the study's lead researcher.
London and others studied 121 women who developed breast cancer between 1976 and 1986 and who previously had undergone a biopsy for benign breast disease.
The women were classified into three groups: those who had non-proliferative breast disease, or non-cancerous lesions; those with proliferative disease, or lesions that showed "a mild overgrowth of cells"; and sufferers of atypical hyperplasia.
Those with proliferative disease had 1.6 times the risk of breast cancer compared with the non-proliferative group. But the women with atypical hyperplasia faced 3.7 times the risk.
The risk of developing breast cancer was 5.9 times higher among pre-menopausal women with atypical hyperplasia and 2.3 times higher among post-menopausal women with it, London said.