High detection rate of breast cancer by mass screening using mammography in Japan.

A trial of mass screening for breast cancer using both mammography and physical examination (independently) was carried out in women over 50 years of age in Tokushima Prefecture. Breast cancer was detected in eight of a total of 950 examinees by mammography alone, and no cases of breast cancer were detected by physical examination. The detection rate of breast cancer was 0.84%, which is very much higher than that obtained by conventional mass screening using physical examination alone. The detection rate increased especially in the sixth and seventh decades of life. All eight detected breast cancers were in the early stage. Based on these results, it is recommended to employ mammography in breast cancer screening for asymptomatic women aged over 50 years.