Benign Breast Conditions and Breast Cancer Risk

Most benign breast changes do not increase a woman's risk for getting cancer. Studies show that only certain very specific types of microscopic changes put a woman at higher risk. These changes feature excessive cell growth, or hyperplasia.

About 70 percent of the women who have a biopsy showing a benign condition have no evidence of hyperplasia. These women do not have an increased risk for breast cancer.

About 25 percent of benign breast biopsies show signs of hyperplasia, including conditions such as intraductal papilloma and sclerosing adenosis. Hyperplasia only slightly increases the risk of developing breast cancer.

The remaining 5 percent of benign breast biopsies reveal both excessive cell growth or hyperplasia and cells that are abnormal which is called atypia. A diagnosis of atypical hyperplasia, as it is called, moderately increases breast cancer risk. Understanding Breast Lumps and Other Changes Index

Source:
National Cancer Institute, National Institutes of Health