Reis Tina, Khazzaka Edwin, Welzel Grit, Wenz Frederik, Hofheinz Ralf-Dieter, Mai Sabine
Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
Medical Clinic, University Medical Center Mannheim, University of Heidelberg, Heidelberg, Germany.
Radiat Oncol. 2015 Jan 31;10:30. doi: 10.1186/s13014-015-0336-5.
Current therapeutic standard for locally advanced rectal cancer is the neoadjuvant radiochemotherapy with total mesorectal excision. Diarrhoea is the main acute side effect, induced by the dose to the small-bowel, frequently leading to a treatment modification. Aim of this study was to analyse the differences between the irradiated small-bowel volumes and the occurrence of acute diarrhea during combined radiochemotherapy for rectal cancer.
45 patients treated with a neoadjuvant radiochemotherapy (three-field box 50.4 Gy; Cetuximab, Capecitabine, Irinotecan) for locally advanced rectal cancer within a prospective phase I/II study were evaluated. Based on the dose-volume histograms, the small-bowel volumes receiving doses of 5, 10 … 45 Gy (V5, V10 …V45) were calculated and compared with the prospectively documented small- bowel toxicities.
There was a statistically significant difference between irradiated small-bowel volumes and the severity of therapy related diarrhoea. The strongest validity concerning the risk of developing a grade 2-3 diarrhoea was seen at a dose level of 5 Gy (V 5) with a small-bowel volume of 291.94 cc. Patients with V 5 > 291.94 cc had significantly more often grade 2-3 diarrhoea, than patients with V5 below this cut-off value (82% vs. 29%; p < 0.0001).
In the inverse treatment planning of rectal caner patients the small-bowel volume receiving 5 Gy should be limited to about 300 cc.
局部晚期直肠癌目前的治疗标准是新辅助放化疗联合全直肠系膜切除术。腹泻是主要的急性副作用，由小肠所受剂量引起，常导致治疗调整。本研究的目的是分析直肠癌放化疗期间照射小肠体积与急性腹泻发生之间的差异。
在一项前瞻性I/II期研究中，对45例接受新辅助放化疗（三野盒式照射50.4 Gy；西妥昔单抗、卡培他滨、伊立替康）治疗局部晚期直肠癌的患者进行评估。根据剂量体积直方图，计算接受5、10…45 Gy剂量（V5、V10…V45）的小肠体积，并与前瞻性记录的小肠毒性进行比较。
照射小肠体积与治疗相关腹泻的严重程度之间存在统计学显著差异。在剂量水平为5 Gy（V5）、小肠体积为291.94 cc时，观察到发生2-3级腹泻风险的最强有效性。V5＞291.94 cc的患者发生2-3级腹泻的频率显著高于V5低于此临界值的患者（82%对29%；p＜0.0001）。
在直肠癌患者的逆向治疗计划中，接受5 Gy照射的小肠体积应限制在约300 cc。
