[Incidence of breast cancer in France and other industrialized countries].

The incidence of breast cancer increased over the last 20 years of the 20(th) century in all industrialized countries. The shape of the trend varied according to country. The increase in the prevalence of risk factors associated with a "western" lifestyle has had a major influence on this increase in countries where incidence was low at the start of the study period. Generalized screening practices, on the other hand, has played a key role in countries where incidence was already elevated in the 1970s. This evolution over time, together with the cohort effect (associated with year of birth), makes analysis and interpretation of the available international data too complex to allow us to quantify the respective contributions of screening, treatments and risk factors to mortality trends, which are beginning to decrease substantially in most countries with elevated incidence rates.