Vetsuisse Faculty, University of Zürich, Winterthurer Strasse 260, 8057 Zürich, Switzerland.
Z Med Phys. 2010;20(3):206-14. doi: 10.1016/j.zemedi.2010.03.008. Epub 2010 Jun 19.
Cancer induction after radiation therapy is a severe side effect. It is therefore of interest to predict the probability of second cancer appearance for the treated patient. Currently there is large uncertainty about the shape of the dose-response relationship for carcinogenesis for most cancer types at high dose levels. In this work a dose-response relationship for lung cancer is derived based on (i) the analysis of lung cancer induction after Hodgkin's disease, (ii) a cancer risk model developed for high doses including fractionation based on the linear quadratic model, and (iii) the reconstruction of treatment plans for Hodgkin's patients treated with radiotherapy. The fitted model parameters for an α/β=3 Gy were α=0.061Gy(-1) and R=0.84. The value for α is in agreement with analysis of normal tissue complications of the lung after radiation therapy. The repopulation/repair parameter R is large, but seems to be characteristic for lung tissue which is sensitive with regard to fractionation. Lung cancer risk is according to this model for small doses consistent with the finding of the A-bomb survivors, has a maximum at doses of around 15 Gy and drops off only slightly at larger doses. The predicted EAR for lung after radiotherapy of Hodgkin's disease is 18.4/10000PY which can be compared to the findings of several epidemiological studies were EAR for lung varies between 9.7 and 21.5/10000PY.
放射治疗后的癌症诱导是一种严重的副作用。因此，预测接受治疗的患者发生第二癌症的概率很有意义。目前，对于大多数癌症类型在高剂量水平下的致癌作用的剂量反应关系的形状存在很大的不确定性。在这项工作中，基于（i）霍奇金病后肺癌诱导的分析，（ii）包括基于线性二次模型的分割的高剂量癌症风险模型的开发，以及（iii）放射治疗霍奇金病患者的治疗计划的重建，得出了肺癌的剂量反应关系。拟合模型参数α/β=3 Gy 的参数为α=0.061Gy(-1)和 R=0.84。α的值与放射治疗后肺部正常组织并发症的分析一致。再增殖/修复参数 R 很大，但似乎是对肺组织的特征，肺组织对分割敏感。根据该模型，小剂量的肺癌风险与原子弹幸存者的发现一致，在约 15 Gy 的剂量处达到最大值，并且在较大剂量处仅略有下降。霍奇金病放射治疗后肺部的预测 EAR 为 18.4/10000PY，可以与几项流行病学研究的发现进行比较，其中肺部的 EAR 在 9.7 至 21.5/10000PY 之间变化。
