Hallquist A, Hardell L, Löfroth P O
Department of Oncology, University Hospital, Umeå, Sweden.
Int J Radiat Oncol Biol Phys. 1993 Dec 1;27(5):1085-9. doi: 10.1016/0360-3016(93)90528-4.
The aim of this investigation was to study previous radiotherapy of malignant diseases as a risk factor for thyroid cancer.
By using the Swedish Cancer Registry all cases of thyroid cancer with another malignant disease at least one year previously and living within the catchment area of our hospital were traced. During 1959-1989 a total of 1056 cases of thyroid cancer were identified. Of these 37 had had another previous malignant disease and they constituted the cases in this study. As controls four persons with at least two malignant diseases, thyroid cancer excluded, were selected for each case from the same cancer registry.
Ten (27.0%) of the 37 patients with thyroid cancer as a second tumor had earlier been irradiated with the treatment dose including the thyroid gland as compared with 34 (24.5%) of the 139 control patients. Eight of the ten cases with previous irradiation of the thyroid gland had papillary cancer. The median latency was 13 years. The estimated radiation dose in the thyroid varied between 3 and 40 Gy. External radiotherapy gave a crude odds ratio of 1.1 with 95% confidence interval = 0.5-2.8 for thyroid cancer. The weighted odds ratio was calculated to 2.3 with confidence interval = 0.5-8.9.
This case-control study gave a non significantly increased odds ratio for thyroid cancer in patients with external radiotherapy including the thyroid gland.
本研究旨在探讨既往恶性疾病放疗作为甲状腺癌的一个危险因素。
通过瑞典癌症登记处追踪了所有在我院服务区域内、至少一年前患有另一种恶性疾病的甲状腺癌病例。在1959年至1989年期间，共确诊1056例甲状腺癌病例。其中37例曾患有另一种恶性疾病，这些构成了本研究的病例组。作为对照组，从同一癌症登记处为每个病例挑选了四名至少患有两种恶性疾病（不包括甲状腺癌）的患者。
37例患有甲状腺癌作为第二种肿瘤的患者中，有10例（27.0%）先前接受过包括甲状腺在内的治疗剂量的照射，而139例对照患者中有34例（24.5%）。先前接受过甲状腺照射的10例病例中有8例为乳头状癌。中位潜伏期为13年。甲状腺的估计辐射剂量在3至40 Gy之间。外照射放疗导致甲状腺癌的粗比值比为1.1，95%置信区间为0.5至2.8。加权比值比经计算为2.3，置信区间为0.5至8.9。
这项病例对照研究显示，接受包括甲状腺在内的外照射放疗的患者患甲状腺癌的比值比虽有升高，但无统计学意义。
