Hildreth N G, Shore R E, Dvoretsky P M
Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, N.Y. 14642.
N Engl J Med. 1989 Nov 9;321(19):1281-4. doi: 10.1056/NEJM198911093211901.
It is well established that exposure to ionizing radiation during or after puberty increases a woman's risk for breast cancer, but it is less clear whether exposure to ionizing radiation very early in life is also carcinogenic. We studied the incidence of breast cancer prospectively in a cohort of 1201 women who received x-ray treatment in infancy for an enlarged thymus gland and in their 2469 nonirradiated sisters. After an average of 36 years of follow-up, there were 22 breast cancers in the irradiated group and 12 among their sisters, yielding an adjusted rate ratio of 3.6 (95 percent confidence interval, 1.8 to 7.3). The estimated mean absorbed dose of radiation to the breast was 0.69 Gy. The first breast cancer was diagnosed 28 years after irradiation. The dose-response relation was linear (P less than 0.0001), with a relative risk of 3.48 for 1 Gy of radiation (95 percent confidence interval, 2.1 to 6.2) and an additive excess risk of 5.7 per 10(4) person-years per gray (95 percent confidence interval, 2.9 to 9.5). We conclude that exposure of the female breast to ionizing radiation in infancy increases the risk of breast cancer later in life.
众所周知，青春期期间或之后暴露于电离辐射会增加女性患乳腺癌的风险，但生命早期暴露于电离辐射是否也具有致癌性尚不清楚。我们对1201名婴儿期因胸腺肿大接受过X线治疗的女性及其2469名未接受过辐射的姐妹组成的队列进行了乳腺癌发病率的前瞻性研究。经过平均36年的随访，辐射组中有22例乳腺癌，其姐妹中有12例，调整后的发病率比为3.6（95%置信区间为1.8至7.3）。估计乳房接受的平均吸收剂量为0.69 Gy。首次诊断出乳腺癌是在辐射后28年。剂量反应关系呈线性（P<0.0001），每1 Gy辐射的相对风险为3.48（95%置信区间为2.1至6.2），每格雷每10（4）人年的附加超额风险为5.7（95%置信区间为2.9至9.5）。我们得出结论，婴儿期女性乳房暴露于电离辐射会增加日后患乳腺癌的风险。
