[Pregnancy and breast cancer: 2 entities with complex interferences. Critical study of the dossier]

The author reviews the epidemiological, biological and clinical data concerning the association of carcinoma of the breast and pregnancy. He discusses, in particular, the therapeutic problems raised by this association. The author attracts attention to the fact that in certain circumstances, pregnancy may aggravate the disease, whilst in others, it seems to protect with regard to the cancer. As far as the therapeutic problems are concerned, he emphasizes in particular, the following conclusions: 1) in cases which require surgery, the prognosis is less poor than generally believed; 2) the total inefficacy of therapeutic abortion is now certain; 3) radiotherapy and chemotherapy should be prohibited during pregnancy; 4) a pregnancy occurring during the years following mastectomy for carcinoma, does not seem to have the unfavourable prognosis which was originally believed.