Breast cancer screening by ultrasonography (US) was carried out in Edogawa ward, Tokyo, between 1990 and 1997. US was performed with real-time equipment using a 7.5MHz probe. Among 36, 972 women screened, 190 breast cancers including 103 early cancers were detected within 7 years. The detectability of breast cancer was 0.51%, and the sensitivity of US was 90.5%. Of the 190 breast cancers, 54.2% were early ; among the latter, 40 (33.8%) were non-palpable. Women in their forties showed the highest detectability of breast cancers, so breast cancer screening with US seems useful for this age group.

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Since 1990, we have been carrying out breast cancer screening by clinical examination using mammography in women visiting our human “Dry Dock” Center. For a total of 15, 928 women screened between November 1990 and June 1998, the recall rate for further examination was 7.8%. Forty-three breast cancers were detected in 42 women, a detection rate of 0.26%. Of these women, 34 had mammographic findings suggestive of malignancy (mass and/or micro-calcification or distortion), and 8 were negative. Among women aged 40-49, nineteen cancers were detected, a detection rate of 0.27%.
The TNM stages of the 43 detected cancers were : Tis, 11.6% ; Stage-0, 25.6% ; St.-I, 30.2% ; St.II, 25.6% ; St-IIIa, 2.3% ; StIIIb, 2.3% ; St?IV, 2.3%, and the detection rate for early breast cancers was 67.4%.
Twenty-five patients were operated on in our hospital. The clinical stage and outcome of these 25 patients in whom cancers were detected by screening were compared with the results of 92 patients who visited the surgical outpatient department of our hospital for clinical evaluation during the same period. Early breast cancers accounted for 76.9% of the screened group, and 47.8% of the outpatient group (p<0.01). Examination of axillary lymph nodes revealed metastates in 12.5% of the screened group and 40.7% of the outpatient group (p<0.02).
These findings indicate that breast screening by clinical examination using mammography is significantly more effective for early detection of breast cancers.

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To investigate the efficacy of mass screening for breast cancer by physical examination, we compared the clinical stage, T, number of lymph node metastases and prognosis of breast cancers detected by mass screening in asymptomatic patients with those in symptomatic patients. A total of 607 asymptomatic patients and 1, 250 symptomatic patients in whom breast cancer was detected by mass screening at the Detection Center of Hokkaido Cancer Society were reviewed. The mean ages and times of screening in the two groups were almost the same. The percentages of patients with clinical stage I, and with Ti, and with no lymph node metastases were higher in the asymptomatic than in the symptomatic patients. On the other hand, the percentages of patients with clinical stage III+IV, and with T3+4, and with more than 5 lymph nodes metastases were higher in the symptomatic patients. The 5 year survival rate of asymptomatic patients (93.2%) was significantly higher than that of symptomatic patients (88.4%). The 10-year survival rate of the asymptomatic patients (84.5%) was not significantly higher than that of the symptomatic patients (79.9%). However, the p value was 0.064. It is considered that the clinical stage of cancers found in outpatient clinics is more advanced than that in symptomatic patients detected by mass screening. Therefore, mass screening for breast cancer by physical examination may be effective for women with no subjective symptoms. Cancers in the asymptomatic patients were smaller than those in the symptomatic patients. Mass screening for breast cancer will increase the indications for breast-conserving surgery and will thus improve the quality of life for patients with breast cancer.

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[in Japanese]

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[in Japanese]

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In order to evaluate the effectiveness of breast cancer screening by clinical breast examination alone in Japan, we carried out a literature review and a case-control study.
Previous studies showed that early-stage breast cancer was more frequent in cases detected by screening than in cases diagnosed at clinics. However, there was no significant difference in the 10-year survival rate between the groups.
We then conducted a case-control study to investigate whether breast cancer screening could reduce mortality due to breast cancer. The screening history of 93 cases and 375 controls in Miyagi and Gunma Prefectures were surveyed. The odds ratio of breast cancer death by participating in the screening within 1 year prior to the diagnosis of breast cancer was 0.93, which was not statistically significant.
The present results along with those of past studies suggest that current breast cancer screening by clinical breast examination alone in Japan is not effective. Introduction of mammography screening needs to be considered in order to prevent breast cancer deaths more effectively.

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During a period 9 years from April 1988 to March 1996, 9, 298 women underwent closer examination after mass screening for breast cancer in Nagano prefecture. These women were divided into two groups according to whether subjective symptoms were present (+) or absent (-) prior to the screening. One hundred forty-one being breast cancers (9.1%) were detected in 1, 553 women with subjective symptoms, being significantly higher than the 122 cases (1.6%) detected in 7, 745 women without subjective symptoms.
Palpation diagnosis was classified into4 grades from a (normal) to d (malignant). The number of cases classified as b was highest, and that of d cases was lowest in both groups. The breast cancer detection rate in d cases was highest, and tended to decrease as the lesion diagnosed more benign in both groups. The breast cancer detection rate in the (+) group was significantly higher than that in the (-) group in a to c cases. Ultrasonographic diagnosis was divided into 5 grades : US I (normal) to US V (malignant). The number of US III cases was highest and that of US IV+V cases was lowest in both groups. The breast cancer detection rate in the US IV+ V cases was highest and tended to decrease as the lesion diagnosed more benign in both groups. The breast cancer detection rate in the (+) group was significantly higher than that in the (-) group from US I+II to US IV+V.
Breast cancers were detected more frequently in the (+) group than in the (-) group, but the proportion of patients with advanced breast cancer in the (+) group tended to be higher.
Therefore, to increase the effectiveness of mass screening for breast cancer, women with subjective symptoms in the breast should be encouraged to visit special diagnostic units rather than undergo mass screening.

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A nationwide survey was performed in an attempt to investigate the distribution of average glandular doses caused by mammography for breast cancer mass screening, and to utilize the data to determine the national guidance level for mammography. A phantom equivalent to a breast with a compressed thickness of 42mm, and glass radio-photo luminescence dosimeters were sent to 104 institutions and facilities. The dosimeters were exposed using a method based on the protocols described in the Mammography Quality Control Manual. The returned dosimeters were then analyzed, and the beam qualities and the entrance surface exposures were determined. Using these values, the average glandular doses were estimated with an accuracy of ±8%. The doses ranged from 0.5 to 3.7mGy. The mean dose and the standard deviation were 1.48mGy and 0.52mGy, respectively. In 91 facilities, the doses were less than 2mGy. Regarding the technical factors for facilities which presented doses of 2mGy or over, it seemed that the doses could be easily reduced to less than 2mGy if the settings of the auto exposure controller (AEC), anti-scatter grid and/or the film-screen system were optimized.

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We sent out questionnaires to hospitals in Aomori to obtain data about their mammographic systems. For the 15 hospitals (employing 17 systems) which completed the questionnaire, we measured exposure dose with film badges, and evaluated the image quality and performance of the equipment. Consequently, one system (5.9%) exceeded the limits of 10% for X-ray tube voltage. Five (29.4%) exceeded the limits of 5% endorsed by the committee for mammographic guidelines. Four (23.5%) satisfied the standards of image quality. Eleven (64.7%) satisfied the exposure dose of less than 3 mGy. One (5.9%) satisfied the image quality and exposure dose specifications.
This study clarified how the mammographic systems were used and indicated how mammographic systems should be improved in order to satisfy standards.

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The use of breast self-examination (BSE) is expected to allow women to become more familiar with their own breast architecture and to consult outpatient breast specialists directly when they find a mass, thus increasing the early detection of breast cancer. Many women, however, fail to palpate significant breast masses due to their poor BSE technique. We theorized that the efficacy of breast cancer screening would improve if accurate instruction in, and performance of BSE was added to routine inspection and palpation by a physician. To this end, we proposed a standard for evaluating BSE performance and investigated the performance level necessary for detecting a palpable breast lump. Three hundred thirty-ne asymptomatic women were screened by a physician (Kotsuma, Y.) via visual inspection and palpation during the period from April to September, 1996. Two hundred fifty of the women had previously undergone a screening examination and instruction in BSE ; however only 53% reported practicing BSE. The subjects were asked to evaluate their own BSE technique and then to perform BSE for the doctors, who also rated them. Each assessment was graded from A to D with A best and D worst. Sixty-seven rated themselves A or B, while only 13 were rated this highly by the physicians (13 as B, none as A) Among 47 subjects referred for further examination, 96% received physician grades below C. In order to master the ability to detect a mass by BSE, women should attain a performance level of B or greater as judged by their physician.

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