Division of Spinal Surgery, Department of Orthopedics, College of Medicine, Korea University, Seoul, South Korea.
Department of Biostatistics, College of Medicine, Catholic University, Seoul, South Korea.
JAMA Netw Open. 2019 Sep 4;2(9):e1910584. doi: 10.1001/jamanetworkopen.2019.10584.
Diagnostic low-dose ionizing radiation has great medical benefits; however, its increasing use has raised concerns about possible cancer risks.
To examine the risk of cancer after diagnostic low-dose radiation exposure.
DESIGN, SETTING, AND PARTICIPANTS: This population-based cohort study included youths aged 0 to 19 years at baseline from South Korean National Health Insurance System claim records from January 1, 2006, to December 31, 2015. Exposure to diagnostic low-dose ionizing radiation was classified as any that occurred on or after the entry date, when the participant was aged 0 to 19 years, on or before the exit date, and at least 2 years before any cancer diagnosis. Cancer diagnoses were based on International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes. Data were analyzed from March 2018 to September 2018.
The primary analysis assessed the incidence rate ratios (IRRs) for exposed vs nonexposed individuals using the number of person-years as an offset.
The cohort included a total of 12 068 821 individuals (6 339 782 [52.5%] boys). There were 2 309 841 individuals (19.1%) aged 0 to 4 years, 2 951 679 individuals (24.5%) aged 5 to 9 years, 3 489 709 individuals (28.9%) aged 10 to 14 years, and 3 317 593 individuals (27.5%) aged 15 to 19 years. Of these, 1 275 829 individuals (10.6%) were exposed to diagnostic low-dose ionizing radiation between 2006 and 2015, and 10 792 992 individuals (89.4%) were not exposed. By December 31, 2015, 21 912 cancers were recorded. Among individuals who had been exposed, 1444 individuals (0.1%) received a cancer diagnosis. The overall cancer incidence was greater among exposed individuals than among nonexposed individuals after adjusting for age and sex (IRR, 1.64 [95% CI, 1.56-1.73]; P < .001). Among individuals who had undergone computed tomography scans in particular, the overall cancer incidence was greater among exposed individuals than among nonexposed individuals after adjusting for age and sex (IRR, 1.54 [95% CI, 1.45-1.63]; P < .001). The incidence of cancer increased significantly for many types of lymphoid, hematopoietic, and solid cancers after exposure to diagnostic low-dose ionizing radiation. Among lymphoid and hematopoietic cancers, incidence of cancer increased the most for other myeloid leukemias (IRR, 2.14 [95% CI, 1.86-2.46]) and myelodysplasia (IRR, 2.48 [95% CI, 1.77-3.47]). Among solid cancers, incidence of cancer increased the most for breast (IRR, 2.32 [95% CI, 1.35-3.99]) and thyroid (IRR, 2.19 [95% CI, 1.97-2.20]) cancers.
This study found an association of increased incidence of cancer with exposure to diagnostic low-dose ionizing radiation in a large cohort. Given this risk, diagnostic low-dose ionizing radiation should be limited to situations in which there is a definite clinical indication.
诊断性低剂量电离辐射具有重要的医学益处；然而，其使用的增加引起了对可能致癌风险的关注。
研究诊断性低剂量辐射暴露后癌症的发病风险。
设计、设置和参与者：本基于人群的队列研究纳入了韩国国家健康保险系统索赔记录中基线年龄为 0 至 19 岁的青少年，纳入时间为 2006 年 1 月 1 日至 2015 年 12 月 31 日。诊断性低剂量电离辐射暴露被定义为任何在参与者年龄为 0 至 19 岁时发生的暴露，或在进入日期之后、退出日期之前发生的暴露，并且至少在任何癌症诊断之前 2 年发生的暴露。癌症诊断基于国际疾病和相关健康问题统计分类第十次修订代码。数据于 2018 年 3 月至 2018 年 9 月进行分析。
主要分析使用人数年作为偏移量，评估暴露与非暴露个体的发病率比值（IRR）。
队列共纳入 12068821 人（6339782 人[52.5%]为男性）。0 至 4 岁者 2309841 人（19.1%），5 至 9 岁者 2951679 人（24.5%），10 至 14 岁者 3489709 人（28.9%），15 至 19 岁者 3317593 人（27.5%）。其中，1275829 人（10.6%）在 2006 年至 2015 年期间接受过诊断性低剂量电离辐射，10792992 人（89.4%）未接受过。截至 2015 年 12 月 31 日，记录了 21912 例癌症。在暴露个体中，1444 人（0.1%）被诊断出患有癌症。在调整年龄和性别后，暴露个体的总体癌症发病率高于未暴露个体（IRR，1.64[95%CI，1.56-1.73]；P<0.001）。特别是在接受计算机断层扫描的个体中，在调整年龄和性别后，暴露个体的总体癌症发病率高于未暴露个体（IRR，1.54[95%CI，1.45-1.63]；P<0.001）。在暴露于诊断性低剂量电离辐射后，许多类型的淋巴造血和实体癌症的发病率显著增加。在淋巴造血癌中，其他髓性白血病（IRR，2.14[95%CI，1.86-2.46]）和骨髓增生异常（IRR，2.48[95%CI，1.77-3.47]）的癌症发病率增加最多。在实体癌中，乳腺癌（IRR，2.32[95%CI，1.35-3.99]）和甲状腺癌（IRR，2.19[95%CI，1.97-2.20]）的癌症发病率增加最多。
本研究在一个大型队列中发现了癌症发病率增加与诊断性低剂量电离辐射暴露之间的关联。鉴于这种风险，诊断性低剂量电离辐射应限于有明确临床指征的情况。
