[in Japanese]

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Mass screening for breast cancer in Nagano prefecture has involved inspection?palpation in addition to ultrasonography. Total examinees between April 1988 and March 1995 amounted to about 336, 000 women, of whom about 78, 000 received further examination. These were divided into 4 groups by district (A, B, C, D). Intergroup differences were seen in the numbers of examinees and the rate of further examinations needed, but not in the rate of breast cancer detected. In women who underwent further examination, the breast cancer detection rate differed significantly among the 4 groups. The rate of breast cancer detected by palpation showed no difference, but that detected by ultrasonography did differ among the 4 groups. In terms of diagnostic accuracy of palpation and ultrasonography by district, sensitivity and positive predictability showed no difference, but specificity and accuracy differed significantly between palpation and ultrasonography by district. Sensitivity and positive predictability did not differ, but specificity and accuracy of palpation were higher than for ultrasonography. The proportion of no ultrasonographic diagnosis differed significantly among the 4 groups. It is becoming apparent that the diagnostic accuracy of palpation and ultrasonography by practitioners differs among districts in mass screening for breast cancer in Nagano prefecture. It will be necessary to devise means of resolving these differences in diagnostic accuracy of palpation and ultrasonography.

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In Japan it is considered that mammography should be introduced with physical examination for the mass screening of breast cancer instead of physical examination alone, which is performed at present. Before the introduction of mammography, a mathematical simulation should be performed to show the reduction in breast cancer mortality by mass screening compared with an unscreened population. A mathematical model of cancer screening devised by the authors was used to estimate the number of deaths due to breast cancer (A) in the screened group and those (B) in the unscreened group within the same population. Then the relative risk (RR) and attributable risk (RD) were calculated as (A/B) and (B-A) respectively. Three methods of mass screening were compared : (1) physical examination (1-year interval), (2) mammography with physical examination (1-year interval), (3) mammography with physical examination (2-year interval). The calculated RR values were 0.85 for (1), 0.60 for (2) and 0.69 for (3). Assuming that the incidence of breast cancer was 100/105 person-years, the calculated RD values were 3.0, 8.1 and 6.2 persons/105 person-years for (1), (2) and (3), respectively. The 95% confidence interval of RR for three methods was over 1.0, and thus the reduction of breast cancer mortality was not statistically significant in the present population. In conclusion, mammography with physical examination may reduce breast cancer mortality in comparison with physical examination alone, but a larger number of women must be screened in order to obtain a significant RR value.

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We studied the ultrasonographic findings of invasive lobular carcinoma of the mammary gland in comparison with its histopathologic images. This type of breast cancer has been increasing in Japan. Out of 55 breasts in 53 cases of invasive lobular carcinoma, confirmed by histopathologic diagnosis between January 1990 and June 1998, we studied 33 breasts with the classical type of lobular carcinoma, excluding 1 breast without any abnormality on the preoperative ultrasonogram, 6 breasts coincidented with ipsilateral invasive ductal carcinoma, and 15 breasts with variant form of lobular carcinoma.
With regard to ultrasonographic findings, we reviewed 6 items-lesion margin, border, posterior echo, depth width ratio, boundary echo, and indentation-and compared them with their histopathologic findings in all 33 cases. Ultrasonography of lobular carcinoma revealed that a coarse margin, indistinct border, absent or weakened posterior echo, comparatively small depth width ratio, and boundary echo or indentation tended to be indistinct. These ultrasonographic findings were considered to reflect the characteristic growth of tumor cells and a poor interstitial reaction of this type mammary carcinoma.
Lobular carcinoma shows a characteristic growth form, which is reflected in the ultrasonographic findings.

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No diagnostic standards for mastopathy other than pathologic examination have been established. In this study, we examined the possibility of diagnosing mastopathy by ultrasonography. Between May 1988 and May 1997, 61 women were diagnosed histologically as having mastopathy and were evaluated retrospectively for ultrasonographic findings. The ultrasonographic findings were classified into three types : cystic, solid, and irregular. The main pathological component in each case that occupied the widest area of the lesion was compared with the ultrasonographic findings. The cases diagnosed as cystic by ultrasonography mostly revealed cystic dilatation of the glands histologically. However we were unable to identify the specific histological components of mastopathy by ultrasonographic in case of the solid or irregular type. The pathological components showing the solid type were mostly adenosis and fibrosis histologically. The ultrasonographic findings of adenosis and fibrosis were mostly similar, except for depth-width ratio. In conclusion, mastopathy should not be regarded as a uniform change, because it consists of several different histologic components. Therefore, it is very difficult to make a diagnosis of mastopathy based only on ultrasonographic findings, except when cystic changes are evident pathologically.

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Mass screening for breast cancer was excluded from the Elderly Health Law in 1998. A high-quality, low-cost replacement is therefore needed. We propose a mass screening format with breast self-examination (BSE). Previously we reported that women should attain a performance level of B or greater in order to demonstrate mastery of BSE. However, this is not easy. Among those who were instructed individually in BSE at yearly intervals, minimal improvement was noted over 3 sessions of yearly mass screening. Therefore, as annual instruction in BSE appears ineffective, the ideal frequency and time period of effective BSE instruction were investigated. One hundred and twenty women who consulted Kotsuma Clinic because of breast diseases between June and July 1997 served as subjects. Twenty nine women (24%) had never been instructed in BSE, while 91 (76%) had. Ten of these (11%) had already attained a performance level of B or greater and were excluded. The remaining 110 women were divided into two groups. Group I were instructed in BSE monthly until they attained level B. Group II were instructed in BSE every 2 to 3 months. Fifty percent of Group I attained level B within 3 months, while only 38% of Group II attained level B within one year. Serial BSE instruction at short intervals appeared most effective. Women with abnormal findings can undergo further evaluation by screening mammography.

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Education in breast self-examination (BSE) and diseases of the breast including risk factors of breast cancer has become indispensable for early detection of breast cancer. We carried out a questionnaire survey of female workers at public health centers and general medical institutions and other women from various backgrounds to evaluate recognition of BSE, performance of BSE, history of breast screening, and breast diseases. As of June 30, 1998, 202 females had replied to the questionnaire. These included 114 public health nurses and nurses, of whom 34 were directly involved in screening for breast cancer (direct group), and 26 were indirectly involved (indirect group). Even in the direct group working at public health centers who had to give BSE instruction and education to examinees in screening, the rate of recognition of BSE was not 100% ; only 61% performed BSE, and only 42% did so monthly. Furthermore, even in this group, only 69% had knowledge of the symptoms of breast diseases, 62% had knowledge of examination methods, and 40% had knowledge of therapy. These results suggest that interest in and knowledge about breast diseases, including details of BSE and risk factors, should first be improved on the examiner's side to make examinees proficient in BSE and adequately understand breast diseases.

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