Rapporteur's report—Epidemiology

It is well known that the incidence rates of breast cancer vary widely among the countries of the world. Of relevance to this conference, rates in Japan are much lower than those in such western countries as the United Kingdom and the United States. The reasons for these differences hold clues to the etiology of breast cancer, and this session focused on epidemiologic studies aimed at providing possible explanations for the international differences in rates.