[Definition of the population groups with high-risk for breast cancer].

Based on the epidemiologic literature, the major risk factors for mammary cancer are discussed. The problem in defining population groups with a high potential for breast cancer stems from the fact that for most of the criteria of higher risk only a two- or threefold increase in incidence is observed. In addition, many of the risk factors are not independent but show interactions with other factors. In the individual woman it is possible to decide whether she has a high potential for developing breast cancer or not, but the criteria for high or low risk are not at present sufficiently contrasted to justify the exclusion of certain low-risk groups from screening procedures.