Iinuma T A, Tateno Y
Nihon Igaku Hoshasen Gakkai Zasshi. 1989 Sep 25;49(9):1091-5.
Incidence of breast cancers in Japanese women is increasing steadily. Mass screening of breast cancer was started in Japan under auspices of Adult Health Promotion Act of the Japanese Government from 1987. As the first screening method, the palpation of breasts is employed at present, but it is expected to be replaced by the mammography. In this report, the risk-benefit analysis is presented between risk of breast carcinogenesis due to radiation and benefit of mass screening of breast cancer. The benefit of mass screening is taken as the net elongation of average life expectancy of women due to survival from breast cancers. The risk of mammography is taken as the net loss of average life expectancy of women due to breast carcinogenesis. In the latter, the latency time and plateau period of radiation carcinogenesis were taken into consideration in the calculation. The results show that the ages at which the benefit and risk become equal are between 30 and 35 years old when dose equivalent of mammography is between 10 and 20 mSv, that are conventionally used. However, the critical age will be reduced to 20 years old if the dose equivalent becomes 1 mSv. Therefore, it is strongly recommended that a low dose mammographic system should be developed in order to achieve 1 mSv for the mass screening of breast cancer of Japanese women. In author's opinion, this is quite feasible by employing a new digital radiography with imaging plate.
日本女性乳腺癌的发病率正在稳步上升。在日本政府《成人健康促进法》的支持下，自1987年起开始了乳腺癌的大规模筛查。作为第一种筛查方法，目前采用的是乳房触诊，但预计将被乳房X线摄影术取代。在本报告中，对辐射导致乳腺癌发生的风险与乳腺癌大规模筛查的益处进行了风险效益分析。大规模筛查的益处被视为因乳腺癌存活而使女性平均预期寿命的净延长。乳房X线摄影术的风险被视为因乳腺癌发生而导致女性平均预期寿命的净损失。在后者的计算中，考虑了辐射致癌的潜伏期和平台期。结果表明，当乳房X线摄影术的剂量当量在10至20毫希沃特之间（这是常规使用的剂量）时，益处和风险相等的年龄在30至35岁之间。然而，如果剂量当量变为1毫希沃特，临界年龄将降至20岁。因此，强烈建议开发一种低剂量乳房X线摄影系统，以便在对日本女性进行乳腺癌大规模筛查时达到1毫希沃特的剂量。作者认为，通过采用带有成像板的新型数字射线照相术，这是完全可行的。
