文章：

现代放疗后二次恶性肿瘤的风险评估

Assessing the risk of second malignancies after modern radiotherapy

原文发布日期：2011-05-19

DOI: 10.1038/nrc3069

类型: Review Article

开放获取: 否

要点：

1. The availability of high-energy beams of photons, protons and carbon ions has contributed to increases in tumour control and the sparing of normal tissues from acute radiation toxicity.
2. Advances in cancer therapies for children have produced impressive prospects for long-term survival. Approximately 80% of children and adolescents treated for cancer survive more than 5 years, but roughly 73% of them develop treatment-related complications. The complication of perhaps greatest concern is the risk for developing a radiogenic second malignant neoplasm (SMN), which can develop years or decades after treatment.
3. Although the patient receives a high dose of therapeutic radiation, which is focused at the diseased tissue, the entire body is exposed to comparatively low doses of unwanted radiation that are caused by radiation leaking from the treatment apparatus and by scattering of the therapeutic radiation within the body.
4. Mechanisms of therapy-related cancers are similar to those of sporadic tumorigenesis, but the carcinogenic potential of low doses of photons is not completely understood, and the uncertainty is much higher for cancer that is induced by charged particles.
5. Epidemiological studies have conclusively shown that some SMNs can develop in tissues that are located in-field (that is, in the path of the therapeutic beam) and out-of-field (outside the path of the therapeutic beam).
6. Recent models predict that particle therapy lowers the risk of SMNs compared with contemporary photon therapies.
7. Regardless of the type of radiation beams used, nascent approaches to personalized, risk-adapted radiotherapy seem to be likely to yield further reductions in risk from out-of-field exposures, and research in genetic susceptibility and radiobiology should help to identify biomarkers of long-term risk in cancer survivors.

要点翻译：

1. 高能光子束、质子束及碳离子束的应用，提升了肿瘤控制率并降低正常组织急性放射毒性的风险。
2. 儿童癌症治疗领域的进展为长期生存带来了可观前景。约80%的儿童及青少年癌症患者生存期超过五年，但其中约73%会出现治疗相关并发症。最令人担忧的并发症当属放射性继发恶性肿瘤（SMN）风险，这种病变可能在治疗结束数年或数十年后出现。
3. 尽管患者接受的高剂量治疗性辐射聚焦于病变组织，但受治疗设备辐射泄漏及体内治疗辐射散射的影响，全身仍会暴露于相对低剂量的非目标辐射。
4. 治疗相关癌症的发生机制与散发性肿瘤相似，但低剂量光子的致癌潜力尚未完全明确，而带电粒子诱发癌症的不确定性更高。
5. 流行病学研究已确证，部分继发恶性肿瘤可发生于靶区内（即治疗射线路径）和靶区外（治疗射线路径外）的组织。
6. 最新模型预测，与当代光子疗法相比，粒子疗法能降低继发恶性肿瘤风险。
7. 无论使用何种放射束，新兴的个性化风险适应放疗方法有望进一步降低靶区外暴露风险，而遗传易感性与放射生物学领域的研究将有助于识别癌症幸存者长期风险的生物标志物。

英文摘要：

Recent advances in radiotherapy have enabled the use of different types of particles, such as protons and heavy ions, as well as refinements to the treatment of tumours with standard sources (photons). However, the risk of second cancers arising in long-term survivors continues to be a problem. The long-term risks from treatments such as particle therapy have not yet been determined and are unlikely to become apparent for many years. Therefore, there is a need to develop risk assessments based on our current knowledge of radiation-induced carcinogenesis.

摘要翻译： 

放疗的最新进展已允许使用不同类型的粒子，如质子和重离子，同时也优化了使用传统放射源（光子）治疗肿瘤的方法。然而，长期幸存者中出现第二原发癌的风险仍然是一个问题。诸如粒子疗法等治疗的长期风险尚未确定，而且可能多年内都不会显现。因此，有必要在我们目前对辐射致癌机制认识的基础上，开展风险评估。

原文链接：

Assessing the risk of second malignancies after modern radiotherapy