[Epidemiologic and prognostic factors of cancer of the breast]

Breast cancer is the most common of all cancers affecting women in France; its frequency increases in countries with a high standard of living. A family history and certain types of mastosis are unquestionable risk factors, although their weight has not yet been well established, but there is no absolute proof that feeding habits (notably fats and alcohol), which have been blamed by some authors, play a role in the genesis of breast cancer. Among the classical prognostic factors, which are necessary for surgical decisions, the size of the tumour, its histological grade and above all the number of axillary lymph nodes involved are the most important. However, a better knowledge of breast cancer biology has yielded factors that seem to be more promising than hormonal receptors, notably the DNA content of tumoral cells and the presence or absence of a protease, procathepsin 52 K, which reflects tumoral aggressiveness. As for the study of oncogens described elsewhere in this monograph, it will provide a better definition of high risk subjects and more precise information on the progress of the cancer.