[Epidemiology of breast cancer]

Leading position and further increase in breast cancer incidence in many countries are the most important facts of the descriptive epidemiology of breast cancer. In the GDR breast cancer incidence amounts to 60 per 100,000 per year. There are large differences in the incidence between populations, which support hypotheses about the life style, especially of diet, as a risk factor for breast cancer. Early age at menarche and late menopause, nulliparity and late age at first birth, breast cancer in first-degree relatives, benign breast disease and radiation increase breast cancer risk. Intake of oral contraceptives does not alter the overall risk for breast cancer. However, there are different results concerning the use in young age and before first full term pregnancy. Case-control studies concerning diet are not yet convincing. The results are discussed with respect to beneficial activities in controlling breast cancer.