Objective: The incidence of breast cancer has progressively increased, making it the leading cause of cancer deaths in Japan. Breast cancer accounts for 20.4% of all new cancers with a reported agestandardized rate of 63.6 per 100 000 women. Methods: The Japanese Guidelines for Breast Cancer Screening were developed based on a previously established method. The efficacies of mammography with and without clinical breast examination, clinical breast examination and ultrasonography with and without mammography were evaluated. Based on the balance of the benefits and harms, recommendations for populationbased and opportunistic screenings were formulated. Results: Five randomized controlled trials of mammographic screening without clinical breast examination were identified for mortality reduction from breast cancer. The overall relative risk for women aged 40-74 years was 0.75 (95% CI: 0.67-0.83). Three randomized controlled trials of mammographic screening with clinical breast examination served as eligible evidence for mortality reduction from breast cancer. The overall relative risk for women aged 40-64 years was 0.87 (95% confidence interval: 0.77-0.98). The major harms of mammographic screening were radiation exposure, false-positive cases and overdiagnosis. Although two case-control studies evaluating mortality reduction from breast cancer were found for clinical breast examination, there was no study assessing the effectiveness of ultrasonography for breast cancer screening. Conclusions: Mammographic screening without clinical breast examination for women aged 40-74 years and with clinical breast examination for women aged 40-64 years is recommended for population-based and opportunistic screenings. Clinical breast examination and ultrasonography are not recommended for population-based screening because of insufficient evidence regarding their effectiveness.
Although the introduction of screening mammography in Japan would be expected to reduce mortality from breast cancer, the optimal screening modality in terms of cost-effectiveness remains unclear. We compared the cost-effectiveness ratio, defined as the cost required for a life-year saved, among the following three strategies: (1) annual clinical breast examination; (2) annual clinical breast examination combined with mammography; and (3) biennial clinical breast examination combined with mammography for women aged 30-79 years using a hypothetical cohort of 100 000. The sensitivity, specificity and early breast cancer rates were derived from studies conducted from 1995 to 2000 in Miyagi Prefecture. The treatment costs were based on a questionnaire survey conducted at 13 institutions in Japan. We used updated parameters that were needed in the analysis. Although the effectiveness of treatment in terms of the number of expected survival years was highest for annual combined modality, biennial combined modality had a higher cost-effectiveness ratio, followed by annual combined modality and annual clinical breast examination in all age groups. In women aged 40-49 years, annual combined modality saved 852.9 lives and the cost/survival duration was 3 394 300 yen/year, whereas for biennial combined modality the corresponding figures were 833.8 and 2 025 100 yen/year, respectively. Annual clinical breast examination did not confer any advantages in terms of effectiveness (815.5 lives saved) or cost-effectiveness (3 669 900 yen/year). While the annual combined modality was the most effective with respect to lifeyears saved among women aged 40 -49 years, biennial combined modality was found to provide the highest cost-effectiveness. (Cancer Sci 2006; 97: 1242-1247) B reast cancer is the most common cancer in Japanese women. According to estimates for 1999, 36 139 new cases of breast cancer were diagnosed and these accounted for 16.1% of all new cases of cancer in women.(1) As the prognosis of breast cancer is closely associated with the clinical stage of the disease, early discovery of the cancer (i.e. secondary prevention) is important for disease control, as well as primary prevention by lifestyle modification.(2) Women aged 40-49 years, having the highest incidence rate of breast cancer, should be targeted by an appropriate screening modality in Japan.The first national guidelines for breast cancer screening, established in 1987, endorsed the use of without mammography for women aged 30 years or over, although there had been no evidence of the effectiveness of breast cancer screening using CBE alone.(3,4) Subsequent studies conducted in Japan indicated that SMG leads to a better sensitivity and disease stage distribution at diagnosis.(5-10) Work to introduce mammography into breast cancer screening has been continuing in Japan, and mammography for women aged 50 years or over was endorsed by the Ministry of Health, Labour and Welfare in 2000, and expanded to include women aged 40 years or over in 2004. It is recommended...
The age-specific sensitivity of a screening program was investigated using a population-based cancer registry as a source of falsenegative cancer cases. A population-based screening program for breast cancer was run using either clinical breast examinations (CBE) alone or mammography combined with CBE in the Miyagi Prefecture from 1997 to 2002. Interval cancers were newly identified by linking the screening records to the population-based cancer registry to estimate the number of false-negative cases of screening program. Among 112 071 women screened by mammography combined with CBE, the number of detected cancers, false-negative cases and the sensitivity were 289, 22 and 92.9%, respectively, based on the reports from participating municipalities. The number of newly found false-negative cases and corrected sensitivity when using the registry were 34 and 83.8%, respectively. In detected cancers, the sensitivity of screening by mammography combined with CBE in women ranging from 40 to 49 years of age based on a population-based cancer registry was much lower than that in women 50-59 and 60-69 years of age ( B reast cancer is the most common cancer among women in Japan.(1) A great deal of effort has been made to improve surgical and radiotherapeutic techniques as well as chemo-endocrine therapies for the management of breast cancer, although the mortality rate from breast cancer still remains high. The early detection of breast cancer is believed to be the best means of reducing this mortality and mammography is the only evidencebased screening technology currently available for this purpose. To reduce the mortality of breast cancer, Japan's Ministry of Health, Labor and Welfare declared in 2004 that mammography should be introduced for breast cancer screening in women 40 years of age or older. In addition, Japan's National Cancer Act, namely the law to promote cancer prevention and improve the quality of cancer screening, was also enforced in April 2007. Therefore, assessment of not only the screening modality, but also the accuracy of such screening programs has become increasingly important.Although mammography is useful for detecting breast cancer in early stages, it is thought that the effectiveness of mammography screening in women from 40 to 49 years of age is lower than that in women 50 years of age and over. (2,3) The dense parenchyma in women before menopause can obscure tumor shadows and this results in the lower sensitivity of mammography screening in women 40-49 years of age. (4) To calculate the proper sensitivity of the screening program, it is necessary to get hold of false-negative cases. A reporting system for false-negative cases from participating municipalities was established in Miyagi Prefecture. However, the report was not a legal duty for the municipalities, so the true number of false-negative cases was difficult to determine.Interval cancers are cases that are diagnosed with no evidence of cancer in the primary screening, but they are diagnosed as breast cancer until further screening ca...
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