[Incidence and prognosis of breast cancer in young women in relation to changes in the risk factor profile].

Trends in breast cancer incidence in women aged 25-44 years are assessed in detail based on data from the population-based cancer registry of Saarland-Germany. Compared to 1968-72, from 1978-82 and 1983-87, a highly significant increase in age-standardised incidence by more than 30% was observed. The increase in incidence was most pronounced among women of 25-29 years of age (relative incidence rate 1978-87, compared to 1968-77: 2.03, 95% confidence interval: 1.11-3.71). The role of changes in prevalence of known and suspected risk factors, mainly the age at the onset of menarche, the age at first birth, parity and early and long-term use of oral contraceptives in adolescence, which may partly explain the observed trends, are discussed. The results have important public health implications, such as the need for extended cancer surveillance and epidemiologic research in the Federal Republic of Germany, and offer a quantitative basis for the development and implementation of future early detection programmes as well as the need for medical care facilities.