Hoffman D A, Lonstein J E, Morin M M, Visscher W, Harris B S, Boice J D
Centers for Disease Control, Atlanta, GA.
J Natl Cancer Inst. 1989 Sep 6;81(17):1307-12. doi: 10.1093/jnci/81.17.1307.
Although exposure to ionizing radiation is a recognized risk factor for breast cancer, the potential hazard from low-dose, fractionated exposures during early breast development has not been thoroughly evaluated. Women with scoliosis represent a valuable population for studying this issue because they are exposed to multiple diagnostic x rays during childhood and adolescence, times when the breast may be highly sensitive to the carcinogenic effects of radiation. A study was conducted of 1,030 women with scoliosis who were seen at four Minneapolis area medical facilities between 1935 and 1965. The average age at diagnosis was 12.3 years; 60% of the women had idiopathic scoliosis. Individual x-ray films were counted and the number per patient ranged from 0 to 618 films (mean, 41.5). On average, the x-ray exposures were given over an 8.7-year period. Ninety percent of the women were located, of whom over 92% responded to a mail questionnaire or telephone interview. The average period of observation was 26 years. Overall, 11 cases of breast cancer were reported, compared with six expected (standardized incidence ratio = 1.82, 90% confidence interval = 1.0-3.0). Excess risk increased with time since exposure and was highest among those followed for more than 30 years (standardized incidence ratio = 2.4). Risk also increased with the number of x rays and with the estimated radiation dose to the breast (mean, 13 rad). These data suggest that frequent exposure to low-level diagnostic radiation during childhood or adolescence may increase the risk of breast cancer.
尽管暴露于电离辐射是公认的乳腺癌风险因素，但早期乳腺发育期间低剂量、分次暴露的潜在危害尚未得到充分评估。脊柱侧弯女性是研究此问题的宝贵人群，因为她们在儿童期和青春期会接受多次诊断性X光检查，而这两个时期乳腺可能对辐射的致癌作用高度敏感。对1935年至1965年间在明尼阿波利斯地区四家医疗机构就诊的1030名脊柱侧弯女性进行了一项研究。诊断时的平均年龄为12.3岁；60%的女性患有特发性脊柱侧弯。对个人X光片进行了计数，每位患者的X光片数量从0到618张不等（平均41.5张）。平均而言，X光暴露持续了8.7年。找到了90%的女性，其中超过92%回复了邮件问卷或接受了电话访谈。平均观察期为26年。总体而言，报告了11例乳腺癌病例，而预期为6例（标准化发病率比=1.82，90%置信区间=1.0 - 3.0）。自暴露以来，额外风险随时间增加，在随访超过30年的人群中最高（标准化发病率比=2.4）。风险也随着X光片数量和估计的乳腺辐射剂量增加（平均13拉德）。这些数据表明，儿童期或青春期频繁暴露于低水平诊断性辐射可能会增加患乳腺癌的风险。
