BACKGROUND: Although the breast cancer incidence rate in Japan is lower than in western countries, the age-specific rates have markedly increased in recent years, along with the problems of declining birth rate and an aging population. MATERIALS AND METHODS: We examined past trends of age-specific breast cancer incidence using data from the Osaka Cancer Registry from 1976 to 2010, and estimated future trends until 2025 based on the changes observed and population dynamics using a log linear regression model. RESULTS: The age-specific breast cancer incidence rate has increased consistently from the 1970s, and the rates have caught up with those of Japanese-Americans in the US. Assuming the increasing tendency of age-specific breast cancer incidence to be constant, the average annual incidence of breast cancer will increase 1.7-fold from 2006-2010 to 2021-2025. Furthermore, the number of patients aged 80 years should increase 3.4-fold. CONCLUSIONS: The medical demand for breast cancer care in Japan may increase explosively in the future, particularly among the elderly. We need to prepare for such a future increase in demand for care, although careful monitoring is needed to confirm these results.
BACKGROUND: Although the breast cancer incidence rate in Japan is lower than in western countries, the age-specific rates have markedly increased in recent years, along with the problems of declining birth rate and an aging population. MATERIALS AND METHODS: We examined past trends of age-specific breast cancer incidence using data from the Osaka Cancer Registry from 1976 to 2010, and estimated future trends until 2025 based on the changes observed and population dynamics using a log linear regression model. RESULTS: The age-specific breast cancer incidence rate has increased consistently from the 1970s, and the rates have caught up with those of Japanese-Americans in the US. Assuming the increasing tendency of age-specific breast cancer incidence to be constant, the average annual incidence of breast cancer will increase 1.7-fold from 2006-2010 to 2021-2025. Furthermore, the number of patients aged 80 years should increase 3.4-fold. CONCLUSIONS: The medical demand for breast cancer care in Japan may increase explosively in the future, particularly among the elderly. We need to prepare for such a future increase in demand for care, although careful monitoring is needed to confirm these results.