In this article we review the current controversy regarding the effectiveness of screening for breast cancer with mammography as well as the current status of mammography in Western countries. Firstly, Danish researchers have cast doubt on the results of randomized controlled trials on the effectiveness of mammography screening (“Is screening for breast cancer with mammography justifiable ?”). We summarize the points made by the above paper and the controversy thereafter. Secondly, the attendance rate for mammography screening has been as high as 70% in the United States, the United Kingdom, the Netherlands and Scandinavian countries. We review the factors behind these high attendance rates and the degree to which mammography screening contributes to the decreasing trend in mortality from breast cancer.

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Mammography for breast cancer screening has become more widespread since the Ministry of Health, Labour and Welfare notified local governments of the 65th Notice of the Elderly Health Law. However, there is still a shortage of qualified doctors skilled in interpreting mammograms. Many short training courses on mammogram interpretation have been offered nationwide. We previously reported that a questionnaire provided easy assessment of the quality of mammography training courses, and that doctors who were more experienced with film interpretation obtained higher scores in post-course film reading tests. This report analyzes answers to the questionnaires distributed at the 3rd and 4th short training courses for instructors in June and July, 2000. Forty-eight doctors participated in the 3rd course, of whom 2% were experienced in reading films of less than 200 cases, 40% had such experience in 201-1, 000 cases, and 58% in 1, 001 cases or more. Forty-five doctors participated in the 4th course, for whom the corresponding figures were 12%, 24% and 64%, respectively. The percentages of doctors who obtained grades A (instructor level) and B (adequate level) in the post-course test were 25% and 56% (A + B = 81%) after the 3rd course, and 27% and 58% (A + B = 85%) after the 4th course, respectively. We recommend that mammography training courses should be stratified according to the film reading experience of the participants in order to tailor programs, determine difficulty, and assure quality.

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We evaluated the results of breast cancer screening by mammography in Sagamihara City. Patients were divided into two groups. Patients in group I all underwent screening by mammography, and group II patients were screened with a physical examination before undergoing mammography if it was indicated. The rate of mammography screening in group I was 1. 8 times higher (62.4%) than in group II (34%). The cancer detection rate and the proportion of early stage cancer were also 8.7 times and 1.6 times higher respectively in group I. Despite the fact that symptomatic cancer diagnosed by screening accounted for more than 70% in both groups, the detection rate of asymptomatic cancer by screening was better in group I (0.31%) than in group II (0.09%). Therefore, we conclude that initial screening by mammography is useful in detecting asymptomatic cancer. However, since many symptomatic patients present for screening, it is necessary to carry out breast cancer screening based on appropriate management.

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We studied the possibility of improving agreement rates for evaluation of parenchymal pattern and density on mammograms by making the evaluation criteria more concrete and quantitative. First, we evaluated mammographic parenchymal patterns in 100 cases by four stages : Group A, according to the mammographic guidelines (I); Group B, based on our own criteria with more objective consideration (II).
We compared the agreement rates among and between the determiners. The average rate of agreement among the determiners was73.7% in Group A and85.6% in Group B. The agreement rates between the determiners, based on Kramer's coefficient, were0.387 in Group A and0.558 in Group B. In both groups, the rate in Group B was higher. In Group C, we repeated the parenchymal pattern determination using Criteria II, following Criteria I with specific explanations/descriptions. The agreement rates were κ=0.334 (I) and κ=0.451 (II). Therefore, improved agreement rates among the determiners were available/obtained. These findings suggest that control of mammographic evaluation scattering can be achieved by using more concrete criteria for parenchymal pattern /density.

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In 2000, the Japanese Ministry of Health and Welfare recommended mammographic mass-screening for breast cancer in women aged 50 or over every other year, whereas traditional physical examination by mass-screening alone was recommended for women aged under 50. We investigated whether ultrasound mass-screening for breast cancer was feasible and sufficiently reliable for women in both of these age groups, and also studied whether it was superior to physical examination alone by reviewing cases of non-palpable breast cancer.
The overall data for ultrasound mass-screening over a period of 14 years showed that the rate of breast cancer detection in women aged under 50 and those aged 50 or more was O.11% and 0.13 %, the sensitivity was 92.9% and 94.9%, and the specificity was 93.5% and 96.1%, respectively, the differences being non-significant. However, we also confirmed that the positive predictive value for women aged under 50 was 1.7%, which was significantly (p<0.005) lower than the value of 3.3% for women aged 50 or over. Furthermore, the rate of recall for a second examination was 7.3 % for women aged under 50, which was significantly (p<0.001) higher than the value of 4.4% for women aged 50 or over.
On the other hand, non-palpable breast cancer detected by ultrasound examination accounted tor 25% of all breast cancers in women aged under 50, all of them were very small tumors less than 10 mm in diameter, and 90% of them were invasive. These results show that mass-screening by physical examination alone overlooks one fourth of all breast cancers in women aged under 50, raising the possibility that these cases would continue to grow into advanced cases in women beyond 50 years of age. We conclude that ultrasound mass-screening is as effective for detection of breast cancer in women aged under 50 as it is for detection in women aged 50 or over, and is superior to mass-screening by physical examination alone.

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Breast self-examination (BSE) is effective for the early detection of breast cancer. We examined the status of BSE in 187 women who completed a questionnaire, which we then subjected to cross-analysis. The women's awareness of BSE correlated well with the frequency of their visits to our institute, but their practice of BSE did not. The most, common reason for not practicing BSE was the difficulty of distinguishing normal breast tissue from abnormal tissue. The women were then given individual instruction by nurses in how to recognize normal breast tissue and how to carry our BSE. Immediately after the session, the women reported that they were able to recognize their normal breast tissue. However, most could not recognize normal breast tissue after one year, although many of them had continued BSE. We suggest that individual BSE instruction is effective in encouraging patients to continue practicing BSE. However, the instruction may need to be repeated several times and the patient's technique should be evaluated.

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