Abstract
Breast cancer screening in Japan actually started in 2004, when mammography was first introduced, and the need for strict quality control began to be promoted under the leadership of the Japan Association of Breast Cancer Screening. However, there have been a surprisingly small number of reports on quality control of detailed examinations. In fact, the standards required by a facility for detailed examinations were established only recently by the Association.
Detailed examination has usually been carried out at hospitals dealing with health insurance. The detection rate of breast cancer diagnosed at these hospitals is known as the “ positive predictive value ” (PPV). The PPV is an index figure representing an individual facility's ability to detect breast cancer by detailed examination, but almost no reports have adopted PPV as a standard for hospital evaluation. Results of detailed examination are reported to both facilities for primary screening and cities, towns and villages, and then the results are registered at municipal health centers and by the prefectural government. The prefectural government collects all reports from municipalities and organizes a central database, from which PPV can be easily calculated.
We analyzed the 3-year screening results for a total population of 83,888 at three primary screening facilities that covered 4/5 of all screenings in Niigata Prefecture. Detailed examinations of 7,364 women were carried out at 105 hospitals, which were selected freely by the responders. The results indicated that PPV could be used as an index showing the ability of individual hospitals to perform detailed examinations.
