Letschert J G, Lebesque J V, de Boer R W, Hart A A, Bartelink H
Radiotherapy Department, The Netherlands Cancer Institute, Amsterdam.
Radiother Oncol. 1990 Aug;18(4):307-20. doi: 10.1016/0167-8140(90)90111-9.
The effects of the volume of irradiated small bowel on late small-bowel tolerance was studied, taking into account the equivalent total dose and type of pre-irradiation surgical procedure. A method was developed to estimate small-bowel volumes in the high-dose region of the radiation treatment using CT-scans in the treatment position. Using this method small-bowel volumes were measured for three-field and AP-PA pelvic treatments (165 cm3 and 400 cm3, respectively), extended AP-PA pelvic treatment (790 cm3), AP-PA treatment of para-aortic nodes (550 cm3) and AP-PA treatment of para-aortic and iliac nodes (1000 cm3). In a retrospective study of 111 patients irradiated after surgery for rectal or recto-sigmoid cancer to a dose of 45-50 Gy in 5 weeks, extended AP-PA pelvic treatment (n = 27) resulted in a high incidence of severe small-bowel complications (37%), whereas for limited (three-field) pelvic treatment (n = 84) the complication rate was 6%. These complication data together with data from the literature on postoperative radiation-related small-bowel complications were analysed using the maximum likelihood method to fit the data to the logistic form of the dose-response relation, taking the volume effect into account by a power law. The analysis indicated that the incidence of radiation-related small-bowel complications was higher after rectal surgery than after other types of surgery, which might be explained by the development of more adhesions. For both types of surgery a volume exponent of the power-law of 0.26 +/- 0.05 was established. This means that if the small-bowel volume is increased by a factor of 2, the total dose has to be reduced by 17% for the same incidence of small-bowel complications.
研究了照射小肠体积对小肠晚期耐受性的影响，同时考虑了等效总剂量和照射前手术方式的类型。开发了一种方法，利用治疗体位的CT扫描来估计放射治疗高剂量区域的小肠体积。使用该方法测量了三野和前后位盆腔治疗（分别为165立方厘米和400立方厘米）、扩展前后位盆腔治疗（790立方厘米）、主动脉旁淋巴结前后位治疗（550立方厘米）以及主动脉旁和髂淋巴结前后位治疗（1000立方厘米）时的小肠体积。在一项对111例因直肠癌或直肠乙状结肠癌手术后接受5周45 - 50 Gy照射的患者的回顾性研究中，扩展前后位盆腔治疗（n = 27）导致严重小肠并发症的发生率较高（37%），而有限（三野）盆腔治疗（n = 84）的并发症发生率为6%。利用最大似然法对这些并发症数据以及文献中关于术后放疗相关小肠并发症的数据进行分析，将数据拟合到剂量反应关系的逻辑形式，并通过幂律考虑体积效应。分析表明，直肠癌手术后放疗相关小肠并发症的发生率高于其他类型手术，这可能是由于粘连增多所致。对于这两种手术类型，均确定幂律的体积指数为0.26±0.05。这意味着，如果小肠体积增加1倍，为使小肠并发症发生率相同，总剂量必须降低17%。
