Histopathologic risk factors for breast cancer in women with benign breast disease.

Mammary epithelial hyperplasia indicates an increased likelihood of carcinoma development as it does in other organs. Prospective studies have demonstrated that in the premammography era about 70% of women undergoing surgical biopsy had no increased risk of cancer and have little if any hyperplastic alteration. About 25% of women have well-developed hyperplastic changes and have a risk elevation, controlled for age, of 1.5-2 times that of the general population. Less than 5% of women have atypical hyperplasia demonstrating some histologic features of carcinoma in situ, which indicates a risk elevation of 4-5 times. This is about one half the risk associated with microscopic carcinoma in situ. Therapeutic implications of these premalignant lesions rest predominantly in their indication for the heightened intensity of subsequent breast cancer surveillance and screening.