[Early detection in the mass screening for breast cancer].

Mass screening for breast cancer has been conducted in Japan mainly by physical examination, defined as a standard method in Law of the Health Services for the Aged. Detection rate of early breast cancer by physical examination ranged between 40 and 50%. To improve the detection rate of breast cancer at the early stage, some screening trials using a film mammography were carried out in recent years. Detection rates of early breast cancer in these trials were reported to be improved largely, suggesting the effectiveness of breast cancer screening would be improved by the screening with film mammography.