Generally, evidence of mortality reduction is required in population-based organized cancer screening. Mammography is the only method that has been shown to be effective for reducing mortality due to breast cancer through randomized controlled trials (RCTs) performed in Western countries. However, these RCTs did not clearly demonstrate the value of screening mammography for women in their 40s, who showed higher breast density in their mammograms. High breast density is more common in women in their 40s than those in their 50s, and in Japanese than in western women.
Breast ultrasonography has often been utilized in breast cancer screening, because of its potential ability to visualize early cancer even in women with dense breast tissue. However, the quality control and interpretation of ultrasonography for breast cancer screening has not been standardized, nor has the effectiveness of ultrasound ever been verified in terms of mortality reduction. The Ministry of Health, Labor and Welfare has launched a national priority research program entitled “Randomized controlled trial on effectiveness of ultrasonography for breast cancer screening”.
To verify the quality and effectiveness of ultrasound for breast cancer screening, a total of 120,000 women aged 40-49 will be enrolled, with randomization into two groups: mammography plus ultrasonography, and mammography alone. The first endpoints are sensitivity and specificity, and the secondary endpoint is the cumulative rate of advanced breast cancer in the two groups. This trial, designated the Japan strategic anti-cancer randomized trial (J-START), is the first large-scale RCT of cancer screening in Japan, following enforcement of the National Cancer Act in 2007.

View full abstract

The urgent objective of breast cancer screening is to reduce the incidence of death due to breast cancer, which has recently been increasing in Japan. Since women in their 5th decade have the highest incidence of breast cancer in Japan, we must think about the importance of screening participants in younger age brackets.
Mammographic breast cancer screening has yielded good results due to the sustained effort of the Central Committee for Quality Control to increase its quality and availability. However, screening of younger women has limitations of sensitivity because of diffusely or unevenly dense breast tissue. Therefore we consider that combined use of ultrasonography is important for screening of young women.
We reviewed the results of our combined mammographic and ultrasonographic screening carried out on a total of 91,882 participants in Tochigi prefecture during a 6-year period from 2000 through 2005. The contribution rates of mammography to the breast cancer detection rates in women in their 5th and 6th decades were 82% and 64%, respectively, and those of ultrasonography were 72% and 71%, respectively. The corresponding figures for mammography in women in their 7th and 8th decades and over were 85% and 89%, respectively, while those for ultrasonography were 63% and 59%, respectively. These results imply that combined use of both mammography and ultrasonography works well by compensating for each other's limitations for women in their 5th and 6th decades.
For women in their 4th decade, the rate of breast cancer detection was low, and the ratio of the effect relative to mass screening cost was low. For women aged between 35 and 39, however, the incidence of breast cancer apparently increased and reached an incidence similar to those for other malignancies. Therefore breast cancer screening for younger women is of social importance, and introduction of ultrasonography to screening of this population is necessary.

View full abstract

We conducted a retrospective review of 2,641 cases of breast cancer treated surgically between April 2000 and March 2007 for which both preoperative mammography (MLO and CC view) and sonography data were available. Among these cancers (overall BC), 202 (7.6%) were detected only by sonography, and were negative by mammography (US-BC). Analysis of age distribution showed that US-BC detected cancers more frequently in women in their thirties (11.9% vs 7.5%) and forties (39.1% vs 26.2%). Non-invasive ductal carcinoma was predominant among the US-BC cases, compared with overall BC (32.7% vs 12.4%). Invasive ductal carcinomas less than 1cm in diameter were more prevalent among US-BC cases than among overall BC (32.8% vs 17.3%). DCIS and invasive ductal carcinomas less than 1cm in diameter comprised 88.9% of US-BC cases, compared with 60% of overall BC. In conclusion, we suggest that sonography should carried out in addition to mammography in order to detect DCIS and early-stage cancer, particularly in women under 50 years old and those with dense breast tissue.

View full abstract

Both patients with, and deaths due to breast cancer have recently been increasing annually. As it is difficult to prevent breast cancer or eliminate its causative factors, mass screening is extremely important to reduce the number of cancer deaths by early detection and treatment.
Mammographic screening is indisputably valuable for reducing breast cancer death, but it must be recognized that some breast cancers are undetectable because of dense breast tissue in premenopausal women. On the other hand, ultrasonography is advantageous in that it can be used for women of all ages and it has no irradiation hazard.
We developed our own guidelines for breast cancer screening in 2004, in order to establish an efficient mass screening system in all cities, towns and villages in Chiba prefecture. This involved the introduction of ultrasonography examination for screening women in their 4th and 5th decades, and for women in their 5th decade in whom breast cancer occurs most frequently, performance of either mammography or ultrasonography in alternate years. Ultrasonography screening was carried out on a total of 79,272 women during a 5-year period from 2002 through 2006. The recall rate was 7.4%, the number of breast cancers detected was 114, and the cancer detection rate was 0.14%. Compared with mammographic screening, ultrasonography screening has the disadvantages of lower objectivity and of lower reproducibility, and the quality is greatly influenced by the ability of doctors and technicians who perform the examination. In order to further promote ultrasonography screening, it is important to establish a system for improving quality control and also to increase the number of qualified technicians.

View full abstract

The first training course in breast ultrasonography hosted by the Subcommittee for Education, Japanese Association of Breast and Thyroid Sonology (JABTS), was held in 2003 and since then has been held more frequently year by year. Thirteen courses were held in 2007, in response to the launch of a national anti-cancer research project entitled “Japan Strategic Anti-cancer Randomized Trial on Breast Cancer (J-START)”. There were two kinds of courses, one for doctors and the other for technologists, and both were held for two successive days. At the end of the courses, examinations were performed on moving and stationary ultrasonograms and the results were evaluated as A, B or C.
Hereafter more ultrasonographers will be needed and the necesssity of training courses will increase.

View full abstract

In order to apply ultrasonography examination to breast cancer screening, it is essential to maintain quality assurance and perform regular inspection of the ultrasonography scanner and probe. After repeated trials, we have succeeded in making a phantom usable for quality assurance, and devised a standard plan for assessing figure quality obtained by ultrasonography for use in breast cancer screening. Due to the rapid development of ultrasonography machines, there are problems with blurring of the focus point, which results from differences in sound speed. Although our standard covers a rather wide range, we think that it can delineate the lowest point of the required standard that a machine should have. The phantom used for quality assurance is useful for daily checking of ultrasound scanners; when a new machine is purchased or if a probe is changed, we obtain control data by using the phantom, and this allows us to detect deterioration of figure quality by periodically obtaining scans of the phantom. We have also selected checking items for daily quality assurance in order to use the machines safely.
The teaching phantom we have devised was originally made of soft materials and it took a long time to obtain one that was almost satisfactory. We are now using it for courses with good results, and conducting an ongoing study using sham lesions inserted into the phantom. Hereafter we will examine the usability of our standard and the method of quality assurance we devised for the course.

View full abstract

BACKGROUND: Minimally invasive breast biopsy technology is now considered a standard of care for the diagnostic evaluation of suspicious breast lesions. The aim of this retrospective study was to evaluate the usefulness of vacuum assisted stereotactic guided breast biopsy in the diagnostic management of mammography-detected calcifications.
PATIENTS AND METHODS: A retrospective analysis was conducted of 243 vacuum assisted stereotactic guided breast biopsies performed at Keio University Hospital from January 2004 to July 2007. The mammograms were categorized according to the Japanese Breast Imaging Reporting and Data System. The distribution of category 2, 3, 4 and 5 was 4.5%, 60.1%, 24.3% and 11.1%, respectively.
RESULTS: The median age was 47 (range 25-81). The pathological examination revealed no carcinoma with category 2 calcification. The final diagnosis of malignancy obtained with category 3, category 4 and category 5 was 19.4% (28/144), 51.8% (29/56) and 81.0% (22/27), respectively. No serious complications including hematoma were observed.
CONCLUSION: Vacuum assisted stereotactic guided breast biopsy was shown to be an accurate and safe technique for the work-up of mammography-detected calcifications. Careful consideration is necessary to decide the indication of biopsy for lesions of J-RADS category 3.

View full abstract

The present technical quality of stereo-guided aspiration biopsy (Mammotome) of breast tissues in Kanagawa Prefecture was studied. Questionnaires were sent to a total of 17 institutions, and answers were obtained from 15 of them. The items of inquiry included the time required for a biopsy (from the start until removal of pressure), number of samples obtained, number of examinees whose biopsy was difficult to perform, and any trial to overcome such difficulties. The answers were analyzed and studied.
The time required to perform a biopsy tended to be longer at institutions dealing with a small annual number of examinees, where a vertical approach was adopted, and where an analog system was used. The number of biopsy samples tended to be higher at institutions dealing with small numbers of examinees, where a lateral approach was adopted, and where an analog system was used. Examinees whose biopsies were difficult to perform were encountered at 80% of the institutions. Several attempts were made to overcome these difficulties, which included thin breasts, calcified lesions located near the breastwork and severely nervous examinees.
It is important to exploit the characteristics of the machine system, make the best use of available instruments, perform a biopsy in as short a time as possible, and maintain a high examination quality. It is also important to share other institutions' experiences and trials. Radiology technicians have a responsibility to optimize the quality control of breast tissue biopsy by establishing good teamwork with doctors and nurses. Thus mutual cooperation in the prefecture as a whole will be beneficial for examinees.

View full abstract

We consider that inclusion of mammography is preferable for breast cancer screening in women attending for “human dock”check-ups. Since 2000, we have been performing breast cancer screening that includes mammography. Since the introduction of mammography, over 400 women have undergone screening for breast cancer every year. The rate of additional examinations has also decreased year by year, and recently has leveled off at about 10% or less. The breast cancer detection rate averages 0.47%, and our approach for screening is considered to be efficient. As a result of our efforts to improve quality, a rate almost equivalent to the national average has been achieved. However, the detection rate for early-stage breast cancer is low, at 25%, even taking into consideration the fact that there are many first-time attendees, and therefore our results in this respect must be considered inadequate.
Since it is thought that the number of breast cancers detected will increase from now on, screening according to age and the combined use of mammography and ultrasonography will need to be considered. We are therefore recruiting ultrasound technicians in order to improve quality further.

View full abstract

[in Japanese]

View full abstract