提高食管癌的放射治疗剂量是否有益？--食管癌三维适形放疗临床Ⅰ/Ⅱ期剂量递增试验

Do the patients with esophageal cancer benefit from higher radiation dose?——Dose escalation of 3-D conformal radiation therapy in the patients with esophageal cancer

背景与目的:提高放疗剂量有可能降低食管癌的局部失败率。本研究试图获得食管癌的三维适形放疗的最大耐受剂量,并观察疗效。方法:剂量从70Gy开始递增到76Gy。所有病例均先大野时常规分割46Gy/23Fx/4.5周,缩野时改用加速超分割,1.5Gy/FX,加量24Gy/16Fx。每完成5例后再加量3Gy。以≥15%的患者发生≥RTOGⅢ级急性放射性损伤为终止剂量递增标准。结果:从2000年7月-2001年7月,共18例患者入组。70Gy和73Gy各5例,76Gy组8例。70Gy组没有≥3级急性和晚期放射性损伤;73Gy水平组≥3级晚期放射性损伤4例(其中2例死亡);76Gy组出现≥3级放射性损伤5例(62.5%),≥3级晚期放射性损伤6例(75%)(其中3例死亡)。结论:从本研究的结果来看,食管癌的放射治疗不应追求高剂量,当食管癌照射剂量超过70Gy以后,放射损伤明显增加。食管癌的剂量递增试验应十分谨慎。

Background and purpose：It may improve local control to increase radiation dose for esophageal cancer.The purpose of the study is to obtain the maximum tolerance dose（MTD）and assess toxicity of 3-D conformal radiation therapy（3-DCRT）for esophageal cancer.Methods：The scheduled dose escalation ranged from 70 Gy to 76 Gy.All patients received conventional fractionation irradiation to a dose of 46 Gy/23 Fx/4.5 weeks,followed by accelerated hyperfractionation irradiation using reduced fields,1.5 Gy twice a day,to a dose of 24 Gy/16 Fx.The criteria for stopping dose escalation was grade ≥3 radiation-induced toxicity in ≥15% patients.Results：From July,2000 to July,2001,18 patients were enrolled.Five patients completed a total dose of 70 Gy and an additional 5 patients received 73 Gy.Eight patients completed a total dose of 76 Gy.No patient occurred grade ≥3 radiation-induced toxicity at the level of 70 Gy.Four patients（80%）experienced grade ≥3 radiation-induced late toxicity（2 patients died of late radiation-induced pneumonitis）at the level of 73 Gy.Five patients（62.5%）experienced grade ≥3 radiation-induced acute toxicity and 6 patients（75%）had grade≥3 late toxicity（1 patients died of late radiation-induced esophagitis,and 2 patients died of late radiation-induced pneumonitis）at the level of 76 Gy.Conclusions：Based on the clinical trial,there were more severe radiation-induced toxicities when the patients with esophageal cancer received more than 70 Gy.