Abstract
In Kochi Prefecture breast cancer screening by mammography (MMG) every 2 years for women aged 40 and over was started in 2004. Screening for breast cancer using a combination of MMG and clinical breast examination (CBE) was performed In Kochi city. In the other 30 districts of Kochi Prefecture, MMG was carried out alone as a screening examination out of a traveling bus. The total number of screened patients was 100,102, of whom 81,957 (81.1%) underwent MMG alone and 19,065 (18.9%) underwent combined MMG and CBE screening between 2004 and 2009. The recall rate was 6.7% with MMG alone and 9.2% with combined MMG and CBE. The numbers of cases of breast cancer detected and the mean rates of detection were 241 and 0.29% and 93 and0.49%, positive predictive value was 4.3% and 5.2%, and the detection rate of early-stage breast cancer was 79.7% and 66.7%, respectively. Only one patient was found to have breast cancer on the basis of CBE alone. Both screening by MMG alone and a combination of MMG and CBE satisfied the respective acceptable values stipulated by the Ministry of Health, Labour and Welfare's Cancer Screening Project Evaluation Committee. We have examined screening films in detail regularly and adopted triple reading for screening by MMG alone. Mammograms in each institution are obligated to be assessed by the Central Committee on Quality Control of Mammographic Screening for improvement of quality management. These data suggest that breast cancer screening with MMG alone may be feasible under precision quality management.
