直肠癌术后调强放疗降低S_(2)/S_(3)以上计划靶区剂量的临床效果

Clinical effect on postoperative intensity modulated radiotherapy of rectal cancer by reducing the dose of planning target volume above S_(2)/S_(3)

目的探讨Ⅱ、Ⅲ期直肠癌术后调强放疗(IMRT)降低S_(2)/S_(3)以上计划靶区(PTV)剂量对小肠高剂量照射体积及患者生存情况的影响。方法选取2017年3月1日至2019年9月30日建湖县人民医院收治的60例Ⅱ、Ⅲ期直肠癌术后患者,随机分为对照组(计划Ⅰ,30例)和试验组(计划Ⅱ,30例)。对照组PTV为全盆腔淋巴结引流区,剂量为50 Gy/25 f。试验组S_(2)下缘以下淋巴结引流区为高危区(PTV 1)剂量为50 Gy/25 f,以及S_(2)下缘以上淋巴结引流区为低危区(PTV 2)剂量为45 Gy/25 f。评估两组靶区均匀性指数(HI)、适形度指数(CI)及危及器官剂量参数[包括小肠45 Gy、50 Gy受照射体积(cc),小肠V 10、V 20、V 30、V 40、V 45、V 50和膀胱V 20、V 30、V 40、V 45、V 50]。患者术后均接受以卡培他滨为基础的同期化疗及辅助化疗。随访记录患者放化疗急性不良反应的发生情况,统计总生存(OS)、无局部复发生存(LRFS)和无远处转移生存(DMFS)。结果对照组、试验组HI分别为0.053±0.004、0.055±0.006,CI分别为0.681±0.033、0.688±0.030,组间差异均无统计学意义(P>0.05)。试验组小肠V 50、V 45低于对照组(P<0.05),而两组小肠V 10、V 20、V 30、V 40及膀胱V 20、V 30、V 40、V 45、V 50差异均无统计学意义(P>0.05)。试验组发生放射性肠炎以0、1级为主,对照组以1、2级为主(P<0.05),两组放射性膀胱炎、放射性皮炎、白细胞减少、血小板减少、血红蛋白减少差异均无统计学意义(P>0.05)。对照组1、3年LRFS分别为93.3%、83.3%,试验组为93.3%、86.7%;对照组1、3年DMFS分别为96.7%、80%,试验组为93.3%、83.3%;对照组1、3年OS分别为100%、86.7%,试验组为100%、90%,两组LRFS、DMFS、OS差异均无统计学意义(P>0.05)。结论Ⅱ、Ⅲ期直肠癌术后IMRT降低S_(2)/S_(3)以上PTV剂量可缩小小肠V 45、V 50高剂量受照体积,降低急性放射性肠炎发生率,且对近期生存情况无明显影响。

Objective To investigate the effect of postoperative Intensity modulated radiotherapy on the high dose irradiation volume of small intestine and the survival of patients with stageⅡandⅢrectal cancer by reducing the dose of PTV above S_(2)/S_(3).Methods 60 postoperative patients with StageⅡandⅢrectal cancer were randomly divided into a control group(PlanⅠ,30 cases)and an experimental group(PlanⅡ,30 cases)in Jianhu County People's Hospital from March 1,2017 to September 30,2019.The prescribed dose of PTV was 50 Gy for the area of total pelvic lymph nodes as control group,50 Gy for the area below S_(2)and 45 Gy for area above S_(2)as experimental group.Homogeneity index(HI)and conformal index(CI),as well as dose parameters of organs at risk including small intestine V 10,V 20,V 30,V 40,V 45,V 50 and bladder V 20,V 30,V 40,V 45,V 50 were compared.All patients received concurrent chemotherapy and adjuvant chemotherapy based on capecitabine.Acute adverse reactions to radiotherapy and chemotherapy,overall survival(OS),local recurrence free survival(LRFS),and distant metastasis free survival(DMFS)were observed.Results The HI of control group and experimental group were 0.053±0.004 and 0.055±0.006 respectively,with no statistically significant difference between two groups(P>0.05).The CI were 0.681±0.033 and 0.688±0.030 in two groups,which were no statistically significant difference(P>0.05).The V 50 and V 45 of intestine in experimental group were significantly lower than control group,which were significant difference(P<0.05).The V 10、V 20、V 30、V 40 of intestine and V 20、V 30、V 40、V 45、V 50 of bladder in two plans were similar(P>0.05).Besides radiation induced enteritis was significant difference(P<0.05),there were no statistically significant differences between the two groups in radiation cystitis,radiation dermatitis,leukopenia,thrombocytopenia,and hemoglobin reduction(P>0.05).1-3 year LRFS 93.3%、83.3%and 93.3%、86.7%.1-3 year DMFS 96.7%、80%and 93.3%、83.3%.1-3 year OS 100%、86.7%and 100%、90%(P>0.05).Conclusions Postoperative IMRT for patients with stageⅡandⅢrectal cancer by reducing the dose of PTV above S_(2)/S_(3)can reduce the exposed volume of high dose V 45 and V 50 in the small intestine,decrease the incidence of acute radiation enteritis,and have no significant impact on short-term survival.