[Early detection of breast cancer by mass screening using mammography]

A mass screening trial for breast cancer using mammography was carried out in Tokushima Prefecture, either itinerant screening in the communities or center screening at the workplace. Craniocaudal and lateral oblique imagings of the breast using two-view film mammography were performed at the first stage of screening. In addition, physical examination of the breast was also performed on subjects independently. A total of 8 cases with breast cancer were found in these trials by mammography alone, and no cases with breast cancer were detected by physical examination. The detection rates were 0.19% in itinerant screening, and 0.92% in center screening, respectively. This was much higher than the level (0.10%) obtained by mass screening using physical examination alone in Japan. Moreover, in elderly patients (age over 50 years), the detection rates were higher (0.54%, 1.21%). The number of clinical stage for cases with breast cancer detected by these screening were 5 cases in TIS and 3 in stage I. Thus, all cases were patients with early-stage breast cancer. From these results, mass screening using mammography should be mandatory for elderly women (over 50 years) with asymptomatic breasts.