Women with benign breast disease have a higher risk for breast cancer, and certain types of breast disease may predict near-term development of breast cancer, according to an article in the July 21 issue of The New England Journal of Medicine.

“Our findings indicate a link between select types of benign breast lesions and the later development of breast cancer,” said Lynn Hartmann, MD, Mayo Clinic oncologist and lead author of the study. “Women who have a breast biopsy that is benign must discuss the possibility of additional risks with their doctors.”

Benign breast disease refers to any lumps or detected by mammogram that have been biopsied and found to not contain cancerous cells. Each year in the United States, more than 1 million women have a breast biopsy with benign findings, and Dr. Hartmann encourages clinicians to look more closely at the type of lesions found.

The Mayo research team is evaluating various possible risk factors for later breast cancer, including age at benign biopsy, family history of breast cancer, and the pathologic findings of the benign lesion. “Our goal is to do a better job of risk prediction for women with various types of benign breast conditions,” said Hartmann.

The study population of 9,087 women was drawn from the Mayo Clinic Surgical and Pathology Indices, identifying women ages 18 to 85 years who had a biopsy of a benign breast lesion during a 25-year period from January 1, 1967, through December 31, 1991. Family histories were obtained at time of follow-up and from Mayo medical record questionnaires.

All benign breast samples were evaluated by a breast pathologist unaware of initial diagnoses or patient outcomes and assigned to one of three categories of benign breast lesions -- non-proliferative, proliferative, and atypical. This information was used to link the risk of subsequent development of breast cancer to specific types of lesions.

The researchers were heartened to find convincing evidence that women with the most common, non-proliferative forms of benign findings had no increased risk for breast cancer as long as they did not have a strong family history of breast cancer. However, for proliferative and atypical disease, the opposite was true, and these lesions pointed to an increased risk of a future breast cancer even when family history was negative.

Hartmann and her colleagues say continued studies of this kind are necessary to help understand the process of breast cancer development and identify patients at higher risk for development of disease.