There is also an increased risk of breast cancer among women with benign breast disease, according to lead researcher Celia Byrne, PhD of Brigham and Women's Hospital and Harvard Medical School and her colleagues. To conduct the study, researchers analyzed biopsy cell samples from 133 post-menopausal breast cancer cases and 610 women with a history of benign breast disease. The breast cells of proliferative breast disease may be normal or abnormal. Proliferative breast disease with abnormal cells is called atypical hyperplasia. According to the researchers, the women with atypical hyperplasia were 3.6 times more likely to develop breast cancer than women with non-proliferative breast disease.
Many physicians think of breast disease as a continuum.
Research has shown that many or most breast cancers do arise from the above sequence. However, some women with hyperplasia or atypical hyperplasia will never develop breast cancer. In general, anything farther along than atypical hyperplasia is usually classified as a cancer. Benign breast disease is fairly common, though current or past use of HRT for five or more years did not further increase the risk of breast cancer among women with proliferative breast disease. Many physicians recommend that women with atypical hyperplasia talk to their physicians about taking steps to help lower their breast cancer risk, especially if they have a strong family history of breast cancer or test positive for BRCA gene mutations.