[Co-existence of chronic myeloid leukaemia and carcinoma of the breast (author's transl)].

Chronic myeloid leukaemia and carcinoma of the breast co-existed in three women. This combination is exceedingly rare. Although the cancerogenic properties of ionizing radiation and cytostatic drugs could be held responsible for the occurrence of two malignant tumours, no definitive conclusions can be drawn in the individual case. Co-existence of leukaemia and carcinoma does not occur more frequently than could be predicted statistically from the incidence of each.