Epidemiology and prevention of breast cancer in the 21st century

The incidence and mortality of breast cancer are high in Western industrialized countries and relatively low in Japan and other Asian countries. In Japan the incidence and mortality of breast cancer have gradually been increasing. Marrying later, having fewer children, a larger intake of fat, dairy products and meats and a larger body mass index in menopausal women may be related to the increased incidence of breast cancer in Japan. A review of risk factors identified from recent epidemiological studies in Japan indicates that obesity after 50 years of age is an important risk factor for postmenopausal breast cancer. Future estimations of cancer mortality and incidence predict that breast cancer will further increase to become a leading cancer in Japan in the 21 st century.