Benign breast conditions and the risk of breast cancer
Most benign breast changes do not increase a woman's risk of getting cancer. Recent 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.
Approximately 70 percent of the women who have a biopsy showing a benign condition have no evidence of hyperplasia. These women are at little increased risk of breast cancer.
About 25 percent of the benign breast biopsies show signs of hyperplasia, including conditions such as intraductal papilloma and sclerosing adenosis. Hyperplasia slightly increases the risk of developing breast cancer.
The remaining 5 percent of benign breast biopsies reveal both excessive cell growth-hyperplasia-and cells that are abnormal-atypia. A diagnosis of atypical hyperplasia , as it is called, moderately increases breast cancer risk.