Bimodal age-frequency distribution of epitheliosis in cancer mastectomies: relevance to preneoplasia.

A census of epitheliosis in 500 consecutive cancer mastectomies has been carried out. The probability of concurrence of this phenomenon with cancer has a bimodal age-frequency distribution. It is high in cancer mastectomies from women in their early 40s, low in the late 50s and high again in the elderly. Epitheliosis during the reproductive life span is regarded as a reversible ovary-dependent abnormality. It is greatly increased in the premenopausal cancerous breast and it is thought that it carries increased risk for cancer initiation. In contrast the probability of epitheliosis in the breast in the elderly cancer patient is only slightly greater than in "noncancerous" post mortem breasts of similar age. Much of this "epitheliosis" may represent, in fact, indolent autonomous cancer though a small proportion could be epitheliosis supported by extraovarian estrogen.