We classified the medical facilities that were involved in breast cancer care in Hiroshima prefecture into four categories and registered them as members of Hiroshima prefectural network for breast cancer care. Sixty-five registered facilities for screening were requested to report the annual number of breast cancer screening participants to our council. The rate of participation in screening calculated on the basis of the numbers reported in 2009 was 19.4%, which was close to the reported rate estimated based on a comprehensive survey of living conditions of people receiving health and welfare benefits.
In Japan, assessment of the rate of participation in screening has been difficult due to the complexity of the screening system. Our Hiroshima model is innovative in that the participation rate for both population-based and opportunistic screening in the prefecture can be calculated collectively.

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In 2009, the US Preventive Services Task Force (USPSTF) recommended that the decision to start regular screening mammography (MMG) before the age of 50 years should be an individual one. They calculated the number needed to invite (NNI) to screening to prevent one death from breast cancer (BC) and concluded that the net benefit is smaller for women aged 40-49yr with its larger NNI than that for women aged 50-59yr. Estimating the NNI by age group is also important in Japan. There has been a need to estimate absolute differences in BC cumulative mortality between women with and without MMG. Since such data are unavailable, we assumed that BC mortality for Japanese women would be the same as that for women without MMG, and that the relative risks were the same as those reported by the USPSTF. Comparison of NNI in Japan with the USPSTF report yielded results that were similar for women aged 40-49yr and 50-59yr, whereas the NNI in Japan was double that reported by the USPSTF for women aged 60-69yr. In Japan, studies for evaluating the balance between the benefits and drawbacks of MMG are needed.

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In 2009, the Japanese government introduced a new project in which a free coupon for breast cancer screening was issued. Our institution provided two mammography buses and visited 11 suburbs of Tokyo places a total of 233 times for screening with the free coupon. We classified the areas visited into two groups: those where we had sent the bus every year (usual areas), and other areas to which we had never sent the bus previously (new area). We also issued questionnaires to the coupon examinees.
The number of mammography screenings conducted was 15,257 (a 71% increase). The recall rate was 6.3%, and the rate of responders for detailed examination was 60.3% in the new areas, being lower than in the other areas. The most serious problem in the new areas was that the rate of early cancer detection was 44.4%, being much lower than in the other areas. In response to the questionnaire items inquiring about womens' motivation for screening, “individual notice’ accounted for the majority of responses, followed by ‘free screening’. In response to the question of how much women were prepared to pay for breast cancer screening, the majority of women stated that they would be willing to pay between 1,000 and 2,000 yen.
In conclusion, the scheme for providing free coupons for breast cancer screening would appear to motivate women who have never undergone screening before. On the other hand, some problems have been exposed. In areas new to screening, a high proportion of advanced cancers were found, and there was a lower rate of response for more detailed examination. The answers received appear to indicate that women prefer to receive individual notice, rather than free screening.

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For precision improvement of breast cancer examinations and additional workup, we examined Category 3, 4 and 5 mammography cases at our hospital. We included 1,624 women who underwent mammography during a one-year period from August 2008 to July 2009. Categories 1 and 2 accounted for 1,458 cases (89%). Category 3 accounted for 128 cases (7.9%), Category 4 33 cases (2.0%), and Category 5 11 cases (0.6%). Breast cancer was found in 5.4% of Category 3 cases, 54% of Category 4 cases, and 100% of Category 5 cases. This indicated that the category classification used for mammography interpretation at our institution was appropriate. Additional workup was performed on the basis of the findings, and the category was judged to be adequate. However, one problem was the large number of Category 3 and 4 cases for which it was unclear whether additional workup was necessary.

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