[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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This study is to examine the relationship between breast density by mammography (MG) and clinical findings for breast cancer. The subjects were 254 cases performed MG, ultrasonography (US), and operation during two years from 2018 to 2019. Breast density was categorized into 4 groups: fatty breast, scattered breast, heterogeneously dense breast, extremely dense breast. Breast density was compared with diagnosed age, BMI, subtype classification, stage, detection opportunity, diagnostic MG category, and US category. According to dense breast, diagnosed age and BMI decreased significantly (p<0.01). There was no difference between 4 groups and the ratio of luminal type. In fatty breast, the ratio of triple negative type was relatively higher than other 3 groups. Breast cancer in fatty breast was detected with tumor awareness. According to dense breast for other 3 groups, tumor awareness increased and screening detection decreased. In dense breast, even diagnostic MG limited to operation cases showed significantly lower diagnostic ability, but the ratio of early breast cancer was equal to other 3 groups. This reason may be that diagnostic US ability compensated. We could not find the accurate conclusion by simply comparing with clinical findings for breast cancer, for breast density was formed by various factors. In the future, we would like to reconsider the breast density after stratifying by effective factors.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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The outbreak of COVID−19 in Japan since March 2020 has caused many local governments and companies to postpone breast cancer screenings. While they have gradually resumed the screenings since June, it is still unclear whether people are willing to undergo the screening. We therefore conducted an Internet survey to analyze how the COVID−19 epidemic had affected women’s intention to undergo breast cancer screening. The survey was conducted from September 3−7, 2020, and valid responses were received from 4,700 women aged 40−69 years nationwide. About half of the respondents were planning to undergo breast cancer screening this year, but 46% said they were changing their plans. Respondents who were older and who had never been screened regularly were more likely to say that they were changing their plans. Background factors, such as the prevalence of COVID−19 in the area of residence and the presence of an infected person in the vicinity, were not associated with the change in the intention of the subjects to undergo the screening examination. These results suggest that breast awareness is important in normal times, even though it is not yet a familiar concept in Japan. We should continue our activities to promote the recognition of this concept. We plan to conduct another survey of the same scale at the end of this year.

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Breast cancer screening in Japan started in 1987, with the introduction of inspection/palpation, and in 2000, mammography screening was introduced. While mammography screening alone showed a beneficial effect of reduced mortality from breast cancer, the effect of screening by inspection/palpation could not be determined. Due to these circumstances, inspection/palpation stopped being recommended in 2016. In a previous survey conducted by us in 2018, we were unable to fully ascertain the implementation system of breast cancer screening in Gunma Prefecture. Therefore, we conducted a questionnaire survey on the implementation status and found that although both mass and individual screenings were conducted based on the guidelines, the percentage of mammography screenings was lower than that of screenings by inspection/palpation, the latter of which are no longer recommended by guidelines. By conducting screening in accordance with the guidelines, it is expected that both the amount of time required for the screening and the screening cost can be reduced. The importance of the self-palpation method has been reported as a measure to compensate for the fact that screening by inspection/palpation is no longer recommended. At the site of breast cancer screening, various efforts are being made by radiological technologists in charge of mammography, including efforts at providing guidance regarding breast self-palpation, asking the examinees questions and performing palpation, reporting known information to doctors, and providing explanations to the examinees based on the radiological technologist’s specialized knowledge, etc. Therefore, it is thought that in order to promote a shift to mammography-only screening, greater importance may be placed on the efforts of the radiological technologists.

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Mammography breast cancer screening in the Philippines is not provided freely, and is not a mandatory requirement in every annual medical examination. The frequency of at which one undergoes mammography examination is left to her own personal choice. In the Philippines, breast cancer is the most common type of cancer affecting women, and is the most common cause of cancer―related death in women. There are not a lot of women who seek mammography, even though early detection of breast cancer by mammography is a proven way to reduce the mortality rate from breast cancer. Therefore, we conducted a questionnaire survey about mammographic breast cancer screening to determine the awareness level and the status in the Philippines. The results of this survey are expected to be contribute to increasing the number of women seeking medical advice and assistance about mammography, for the early detection of breast cancer. The results of the survey showed that 95.5% of the respondents understand the importance of mammography for breast cancer detection, but many factors such as pain, embarrassment, high cost, lack of opportunity, etc., greatly affects their willingness to seek out and receive mammographic examinations regularly. Awareness of the benefits of health insurances, such as those provided by PhilHealth, may lead to better compliance with mammographic examinations.

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To reduce inter- and intra-observer variability in mammographic density estimation, a method for more objective assessment was jointly created by the Japan Central Organization on Quality Assurance of Breast Cancer Screening and the “Research on appropriate information provision for breast cancer screening” group. The aim of this study was to verify the validity of this method for breast cancer diagnosis based on mammographic density. [Subjects and methods] Data of a total of 250 patients (283 lesions) who underwent surgery for breast cancer at our institution from December 2018 to March 2019 were evaluated. Cases with postoperative recurrences and of mammography performed at other institutions were excluded. The subjects ranged from 28 to 95 years old, with a mean age of 50 years. Two qualified breast radiologists reevaluated the mammographic densities independently, and a final classification was made by consensus. The detectability of each lesion was also evaluated in the same fashion. [Results] The compositions of the breasts were distributed as follows: fatty, 2.8%; scattered fibroglandular densities, 52.0%; heterogeneously dense, 37.6%; extremely dense, 7.6%. The detection rate of breast cancer according to the breast composition was 87.5% in cases with a fatty breast, 81.2% in cases with scattered fibroglandular densities, 66.0% in cases classified as heterogeneously dense, and 45.0% in cases classified as extremely dense. [Discussion and conclusion] The detectability of breast cancer in each group of mammographic density was almost identical to that reported from previous studies, and it was proved to decrease in dense breasts. As a next step, it is necessary to verify that this assessment can reduce inter- and intra-observer variability in mammographic density estimation in daily practice.

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Recently, dense breast program, whether to report breast composition to women who have undergone screening has become an important issue. For qualitative assessment of the breast density, various software programs have been developed and installed on the mammography apparatus. For Quantra®, the cutoff values have been calculated in Europe and the United States, but there are no reports of the optimal cutoff values for Japanese and other Asian women. We examined the optimal cutoff values for Quantra® in Japanese women. The results showed that the cutoff values for discriminating between dense breasts and non-dense breasts was 26%. When the breast thickness was less than 30 mm, it tended to be visually assessed as having a higher density, but the software cutoff value was 32%. Therefore, it was verified that it was different from 30 mm or more. Quantitative judgment may be inferior to the assessment of experienced interpreters, but we think that software-based quantitative judgment may be helpful in cases which evaluation is divided among the interpreters.

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The software for quantification of breast density measures the breast density in each pixel, based on the data in mammography images and the imaging conditions. The software has realized the function of measuring the “area ratio of mammary gland tissue to the fat tissue within the entire breast mammogram（hereinafter, FG%）.” In particular, the FG% is an epoch-making parameter, that is highly useful for determining the breast composition in Japan. We sought to assess the breast composition assessment threshold using right mediolateral oblique（MLO）images from 433 patients. However, discrepancies between the FG% and visual assessment were noted in some of the images. We identified compressed breast thickness（hereinafter, CBT）and amount of subcutaneous fat as the reasons for these discrepancies. The CBT and FG% were inversely correlated. In mammary glands with a small CBT, the amount of fat is also small, and the FG% value is higher than the visually observed value. A CBT of less than 30mm is classified as “apparently high breast density.” On the other hand, there was a group with very large amounts of subcutaneous fat to ignore its impact. In the analysis of the amount of fat in the breast, a CBT of 46mm was defined as a “relatively low breast density, ” in which the FG% values were lower than the visually observed values. In this group, patients with an intramammary extragland fat area（hereinafter, ExFat）of ≥200cm3 in the breast were considered to have extremely high amounts of subcutaneous fat. In the groups of patients with “apparently high breast density, ” with a CBT of < 30mm and “relatively low breast density, ” with a CBT of ≥46mm, patients with ExFat values of ≥200cm3 were subjected to correction of the measured FG% values. As a result, the κ coefficient with the visual assessment by the author increased from “moderate concordance ” to “high concordance. ” With this correction, the usefulness of the FG% as an assessment measure is expected to increase, with reduces discrepancies from the visual assessment.

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This study was aimed at analyzing the breast compositions of 807 patients included in the database of digital mammography, and to clarify the relationship between compositional differences and the mean glandular dose (MGD). Mammographic images of the breast composition of 807 patients, obtained us-ing 5 models of equipment at 4 facilities, were evaluated at four points according to established mam-mography guidelines. The images revealed four types of breast composition, which were divided into further groups: high-density breasts and non-high-density breasts. Furthermore, the effects of differ-ences in the breast composition on the MGD were analyzed. The study revealed that 9.5% of the 807 breasts were almost entirely fatty, 43% had scattered areas of fibroglandular densities, 40% were heterogeneously dense, and 7.5% were extremely dense, and that with increasing age of the women, the proportion of almost entirely fatty breasts, as well as of breasts with scattered areas of fibroglandular densities increased, whereas that of the heterogeneously dense breasts and extremely dense breasts decreased. It was also found that the MGD became approxi-mately 16% to 20% higher in high-density breasts than in non-highdensity breasts. The results of breast composition analysis showed the same trend as those reported previ-ously in Japan. However, it was revealed that high-density breasts have a higher MGD than the nonhigh-density breasts.

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Quality control of breast X-ray equipment is essential to obtain clear images of calcifications and lumps that are characteristic of early-stage breast cancer. The method described in the digital mammography guideline is the widely accepted method for quality control. Although image quality evaluation is often conducted using a phantom, X-ray output measurements are not routinely taken. Here, we developed a simplified method of dosimetry for mammography and distributed it to clinical facilities, established a regional cooperative quality control liaison group, and started to operate it at the facilities. We also developed a quality management program to collect the data, through a web application. Quality management checks that are conducted every six months include the constancy test: reproducibility, tube voltage characteristics, tube current time product characteristics, and half-value layer measurement, and daily management is conducted at the inspection conducted at the start of use of the equipment daily. Table, HTML, and Script were built for each test, and registration/update/removal/list and group display programs were developed. By allocating identical user IDs and passwords to users, the data can be shared, and the list and graphic display make it possible for users to visualize the device management situation easily. The mammography DRL is supposed to be evaluated by AGD. As the half-layer characteristics of the invariance test were stable, the AGD that the device was currently showing could be indicated by using the half-layer and air kerma as part of routine management. We want to promote the use of this management system in clinical practice, so that the users can easily manage breast X-ray equipment.

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