Cancer：科学家首次提出射线暴露或和恶性甲状腺癌直接相关

  在1986年切尔诺贝利核电站事故后，加利福尼亚大学的研究人员首次证实，放射性碘的暴露或和患恶性甲状腺癌直接相关。
  文章中，研究者对切尔诺贝利核电站事故后20年来被诊断出的甲状腺癌个体进行检测发现，当年事故发生后高甲状腺辐射剂量和恶性肿瘤发生直接相关。研究者Lydia Zablotska表示，我们此前研究发现放射性碘的暴露会以剂量依赖的方式明显增加个体患甲状腺癌的风险，而本文研究则显示射线照射同样和恶性甲状腺癌发生直接相关，相关研究发表在Cancer杂志上。
  研究者表示，这些射线暴露的个体应当定期进行甲状腺癌的筛查，因为甲状腺癌是一种容易快速扩散的恶性癌症，而医生们也应该清楚和放射相关的肿瘤的发病机制，从而为更好地监测恶性癌症的发生提供帮助。
  甲状腺的良性包囊肿瘤又称为滤泡腺瘤，通常利用和治疗甲状腺癌一样的方法来进行治疗，即移除甲状腺，随后给予病人一定的药物来易患其机体“丢失”的激素；对于病人来讲终生的激素补给疗法往往非常昂贵。甲状腺癌通常在儿童中非常罕见，发病率每年一百万人中不到1例；而在成年个体中大约每年在10万人中就会诊断出13例。
  然而在白俄罗斯的人群研究中，研究者却在11664名个体中诊断出了158例甲状腺病例，这些接受高剂量放射的个体往往更易于患实体瘤或弥散状突变甲状腺癌，而且其更具有侵袭力，容易扩散至淋巴管中而且在甲状腺中同时引发许多癌症损伤病灶。（转化医学网360zhyx.com）
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Analysis of thyroid malignant pathologic findings identified during 3 rounds of screening (1997-2008) of a cohort of children and adolescents from belarus exposed to radioiodines after the Chernobyl accident
Cancer  DOI: 10.1002/cncr.29073
Lydia B. Zablotska MD, PhD1,*, Eldar A. Nadyrov MD2, Alexander V. Rozhko MD, PhD2, Zhihong Gong PhD3, Olga N. Polyanskaya MD2, Robert J. McConnell MD4, Patrick O'Kane MD5, Alina V. Brenner MD, PhD6, Mark P Little PhD6, Evgenia Ostroumova MD6, Andre Bouville PhD6, Vladimir Drozdovitch PhD6, Viktor Minenko PhD7, Yuri Demidchik MD8, Alexander Nerovnya MD8, Vassilina Yauseyenka MS2, Irina Savasteeva MD2, Sergey Nikonovich MD2, Kiyohiko Mabuchi MD, DrPH6 andMaureen Hatch PhD6
BACKGROUND
Recent studies of children and adolescents who were exposed to radioactive iodine-131 (I-131) after the 1986 Chernobyl nuclear accident in Ukraine exhibited a significant dose-related increase in the risk of thyroid cancer, but the association of radiation doses with tumor histologic and morphologic features is not clear.
METHODS
A cohort of 11,664 individuals in Belarus who were aged ≤18 years at the time of the accident underwent 3 cycles of thyroid screening during 1997 to 2008. I-131 thyroid doses were estimated from individual thyroid activity measurements taken within 2 months after the accident and from dosimetric questionnaire data. Demographic, clinical, and tumor pathologic characteristics of the patients with thyroid cancer were analyzed using 1-way analysis of variance, chi-square tests or Fisher exact tests, and logistic regression.
RESULTS
In total, 158 thyroid cancers were identified as a result of screening. The majority of patients had T1a and T1b tumors (93.7%), with many positive regional lymph nodes (N1; 60.6%) but few distant metastases (M1; <1%). Higher I-131 doses were associated with higher frequency of solid and diffuse sclerosing variants of thyroid cancer (P < .01) and histologic features of cancer aggressiveness, such as lymphatic vessel invasion, intrathyroidal infiltration, and multifocality (all P < .03). Latency was not correlated with radiation dose. Fifty-two patients with self-reported thyroid cancers which were diagnosed before 1997 were younger at the time of the accident and had a higher percentage of solid variant cancers compared with patients who had screening-detected thyroid cancers (all P < .0001).
CONCLUSIONS
I-131 thyroid radiation doses were associated with a significantly greater frequency of solid and diffuse sclerosing variants of thyroid cancer and various features of tumor aggressiveness.