Imaoka Tatsuhiko, Ishii Nobuyoshi, Kawaguchi Isao, Homma-Takeda Shino, Doi Kazutaka, Daino Kazuhiro, Nakanishi Ikuo, Tagami Keiko, Kokubo Toshiaki, Morioka Takamitsu, Hosoki Ayaka, Takabatake Masaru, Yoshinaga Shinji
a National Institute of Radiological Sciences, Radiobiology for Children's Health Program, Research Center for Radiation Protection , Chiba , Japan ;
d Radiation Effect Accumulation and Prevention Project, Fukushima Projects Headquarters , Chiba , Japan ;
Int J Radiat Biol. 2016 Jun;92(6):289-301. doi: 10.3109/09553002.2016.1152413. Epub 2016 Mar 11.
Purpose Second cancers are among the most serious sequelae for cancer survivors who receive radiotherapy. This article aims to review current knowledge regarding how the risk of radiotherapy-associated second cancer can be minimized by biological measures and to discuss relevant research needs. Results The risk of second cancer can be reduced not only by physical measures to decrease the radiation dose to normal tissues but also by biological means that interfere with the critical determinants of radiation-induced carcinogenesis. Requirements for such biological means include the targeting of tumor types relevant to radiotherapy-associated risk, concrete safety and efficacy evidence and feasibility and minimal invasiveness. Mechanistic insights into the process of radiation carcinogenesis provide rational approaches to minimize the risk. Five mechanism-based strategies are proposed herein based on the current state of knowledge. Epidemiological studies on the joint effects of radiation and lifestyle or other factors can provide evidence for factors that modify radiation-associated risks if deliberately controlled. Conclusions Mechanistic and epidemiological evidence indicates that it is possible to develop interventional measures to minimize the second cancer risk associated with radiotherapy. Research is needed regarding the critical determinants of radiation-induced carcinogenesis available for intervention and joint effects of radiation and controllable factors.
目的 对于接受放疗的癌症幸存者而言，二次癌症是最为严重的后遗症之一。本文旨在回顾有关如何通过生物学措施将放疗相关二次癌症风险降至最低的现有知识，并讨论相关研究需求。结果 二次癌症风险不仅可以通过减少对正常组织辐射剂量的物理措施来降低，还可以通过干扰辐射致癌关键决定因素的生物学手段来降低。此类生物学手段的要求包括针对与放疗相关风险的肿瘤类型、具体的安全性和有效性证据以及可行性和微创性。对辐射致癌过程的机制性见解为将风险降至最低提供了合理方法。基于目前的知识状况，本文提出了五种基于机制的策略。关于辐射与生活方式或其他因素联合效应的流行病学研究，如果进行刻意控制，可以为改变辐射相关风险的因素提供证据。结论 机制和流行病学证据表明，有可能制定干预措施以将与放疗相关的二次癌症风险降至最低。需要针对可用于干预的辐射致癌关键决定因素以及辐射与可控因素的联合效应开展研究。
