Precancerous mastopathie: structural and biological considerations.

The clinical and biological correlates of specifically classified non invasive breast lesions were compared with those of invasive breast cancer. Lesions classified as precancerous mastopathy and in situ carcinoma were shown to be related to invasive cancer, structurally, temporally, antigenically and in terms of some, but not all risk factors. Mammary carcinogenesis seems to be a discontinous step wise process in which the development of precursor lesions and the precursor to invasive progression are separable phenomena. It appears that different constellations of risk factors may selectively influence one or the other of these steps. Of particular interest are data which suggest that oral contraceptives (OC) favor the precursor to invasive transition in women whose grandmothers and/or aunts had breast cancer but impede this step in women without a family history of breast cancer. There is need for registries of breast diseases which routinely collect data on the clinical and analytical characteristics of specifically classified non invasive as well as invasive breast lesions, derived from the same population over the same time period. Our ability to specifically reduce morbidity and mortality from breast cancer may be more dependant on a better understanding of the development and progression of precursor lesions than on a continued preoccupation with already invasive breast cancers.