[Epidemiology of breast carcinoma]

With the aim of strengthening epidemiological knowledge on breast cancer, the authors analyze the geographical and temporal distribution of mortality and incidence of the neoplasy in Italy and other countries in the world; attention is focused on recent years and on the influence that the year of birth, the period and age of death have on Italian mortality trend. Analysis of the latest available data confirm the great variability in distribution of breast cancer in different countries of the world, with greater frequency in economically advanced western countries, urbanized and industrilized areas, white women and in higher socio-economic classes. The incidence of breast cancer in the world shows a continuous increases which is more evident and rapid in the countries and among the ethnic groups that were until now in lower risk categories. In Italy, during the period between 1950-88, there is a steady increase in the mortality rate, more evident in the first 20 years. The cumulative rates 25-49 years and 50-75 years demonstrates that the essential contribution to the trends is due to the mortality of elderly women. It is plausible that this trend is influenced by the increased survival, although a different cohort effect due to the exposure to different risk factors is possible. The cohort analysis of mortality shows a sharp cohort effect: the mortality increases in an evident way for all cohorts until those born in 1925, afterwhich we find a tendency towards reduction. The identification of specific reasons that are the basis of the observations can contribute to the knowledge of breast cancer eziology.