食管癌放射治疗技术的进展

摘要

Objective: Radiotherapy with concurrent chemotherapy and surgery represent the main treatment modalities in esophageal cancer. The goal of modern radiotherapy approaches, based on recent technological advances, is to maximize the therapeutic gain ratio while minimizing post-treatment complications by improving the gross tumor volume and clinical target volume definitions (positron emission tomography-based planning), reducing interfraction motion (image-guided radiotherapy, such as Varian' s Trilogy system, Elekta' s Synergy system, Siemens' s Artiste system and Tomotherapy system) and intrafraction motion (4D CT imaging and respiratory-gated radiotherapy), and by better dose delivery to the precisely defined planning target volume (intensity-modulated radiotherapy and proton therapy). Although the dose escalation concept is controversial, reduction of radiotherapy-related toxicity can be reduced by means of modern radiotherapy technique and a solid foundation can be laid for the improvement of clinical results in esophageal cancer. The article attached some importance to the utility of PET/CT in treatment planning designing of esophagus cancer radiotherapy, intensity-modulated radiotherapy, tomotherapy, image-guided radiotherapy, four-dimensional CT, respiratory gating and proton radiotherapy and summarized the technical progress in esophagus cancer radiotherapy and pointed out that an prudent attitude should be taken for the usage of PET/CT in treatment planning designing due to insufficient supporting data in spite of growing utility of PET/CT in radiotherapy. In the near future, better clinical effects of radiotherapy in esophagus and gastro-esophageal joint cancer will be acquired by developing and applying new techniques and methods.%同步放化疗和手术是食管癌的主要治疗模式.不断发展的现代放疗手段的目标是通过改进GTV、CTV勾画(基于PET的计划设计),减少分次间(影像引导放疗手段,如Varian的Trilogy、Elekta的Synergy、Siemens的Artiste、Tomotherapy)和分次内(4DCT成像和呼吸门控)的器官运动,实现最佳的剂量分布(调强放疗和质子治疗),在最大可能提高治疗增益比的前提下,使疗后并发症的发生率降至最低.尽管食管癌靶区剂量递增的概念一直存在争议,但通过现代放疗技术可降低放疗相关毒性反应,从而为提高食管癌放疗的临床结果打下坚实的基础.本文围绕PET/CT在食管癌放疗计划设计中的作用、调强适形放射治疗,断层放疗(Tomotherapy),图像引导放疗(IGRT)、四维CT和呼吸门控技术和质子放疗对近年来食管癌放疗技术的发展进行了概述.指出,尽管PET/CT在放疗计划制定中的应用越来越多,由于目前仍缺乏足够的支撑数据,在放疗计划制定过程中应用PET或PET/CT应持谨慎态度.在今后临床实践中可通过进一步应用和研究新技术和新方法以尽可能提高食管癌和胃食管结合部肿瘤的放疗效果.