宫颈癌患者容积旋转调强放疗时BMI及治疗体位与急性放射性肠炎的相关性研究

Effect of body positions and body mass index on dosimetry and acute radiation enteritis in cervical cancer patients undergoing volumetric modulated arc therapy

目的探讨宫颈癌患者容积旋转调强放疗时BMI及治疗体位与急性放射性肠炎的相关性。方法收集2020年8月至2022年5月浙江大学医学院附属杭州市肿瘤医院37例和浙江金华广福肿瘤医院67例共104例宫颈癌患者,按照纳排标准最终入组96例患者。按患者的BMI分为正常及以下组(<24 kg/m^(2))和偏胖及以上组(≥24 kg/m^(2)),再按治疗体位分为俯卧位与仰卧位;交叉组合分为4个亚组,A组为BMI≥24 kg/m^(2)且俯卧位20例,B组为BMI<24 kg/m^(2)且仰卧位40例,C组为BMI<24 kg/m^(2)且俯卧位23例,D组为BMI≥24 kg/m^(2)且仰卧位13例。采用智能勾画软件勾画小肠和直肠等危及器官,确认靶区后由放射物理师进行计划设计优化,分别记录4组患者小肠和直肠的放射剂量体积关系,统计并分析4组患者急性放射性肠炎的发生情况。结果二元logistic回归分析显示,V40_R(40 Gy等剂量线包绕的直肠体积占比)是发生Ⅱ级及Ⅱ级以上急性放射性直肠炎的危险因素(P<0.05),ROC曲线显示V40_R预测发生Ⅱ级及Ⅱ级以上急性放射性直肠炎AUC为0.927,最佳截断值为45%,灵敏度为0.926,特异度为0.826。V40_R<45%组Ⅱ级及Ⅱ级以上急性放射性直肠炎发生率为3.4%,V40_R≥45%组发生率为67.6%。V40_R<45%组中不同BMI、治疗体位的亚组间Ⅱ级及Ⅱ级以上急性放射性直肠炎发生率比较差异均无统计学意义(均P>0.05),而V40_R≥45%组中4个亚组Ⅱ级及Ⅱ级以上急性放射性直肠炎发生率比较差异均有统计学意义(均P<0.05);进一步两两比较发现,A组与D组发生率的差异有统计学意义(P<0.05),说明仰卧位优于俯卧位。结论采用容积旋转调强放射治疗技术下急性放射性肠炎发生率和患者治疗体位相关,应该尽量采用仰卧位体位。同时尽量将直肠V40_R控制在45%以下以降低急性放射性直肠炎的发生率,BMI≥24 kg/m^(2)患者建议采用仰卧位可显著降低Ⅱ级及Ⅱ级以上急性放射性直肠炎的发生率。

Objective To investigate the correlation between BMI,treatment position,and radiation-induced enteritis in patients with cervical cancer during volumetric modulated arc therapy.Methods A total of 104 patients with cervical cancer were enrolled from Zhejiang University School of Medicine,Hangzhou Cancer Hospital(37 cases),and Zhejiang Jinhua Guangfu Cancer Hospital(67 cases)from August 2020 to May 2022.According to the inclusion and exclusion criteria,96 patients were finally included.The patients were classified into two groups based on BMI:normal and below group(BMI<24 kg/m^(2))and overweight and above group(BMI≥24 kg/m^(2)).They were further divided based on treatment positions:prone and supine.The four groups were formed as follows:Group A(BMI≥24 kg/m^(2),prone position,20 cases),Group B(BMI<24 kg/m^(2),supine position,40 cases),Group C(BMI<24 kg/m^(2),prone position,23 cases),and Group D(BMI≥24 kg/m^(2),supine position,13 cases).An artificial intelligence-based automatic segmentation software was employed to delineate the organs-at-risk(OAR),After confirmation by two senior doctors,the treatment plan was designed and optimized by physicist.The radiation dose-volume relationships of the small intestine and rectum were recorded,and incidence of acute radiation enteritis in the four groups was statistically analyzed.Results Binary logistic regression analysis showed that V40_R(the proportion of rectum volume encompassed by the 40 Gy isodose line)was a risk factor for grade Ⅱ and above radiation enteritis(P<0.05)with an AUC of 0.927,optimal cutoff value of 45%,sensitivity of 0.926,and specificity of 0.826 respectively.The incidence of grade Ⅱ and above radiation enteritis was 3.4%in the V40_R<45%group,and 67.6%in the V40_R≥45%group.There were no statistically significant differences in the incidence of grade Ⅱ and above radiation enteritis among the subgroups with different BMI and treatment positions in the V40_R<45%group(all P>0.05).However,there were statistically significant differences in the incidence of grade II and above radiation enteritis among the four subgroups in the V40_R≥45%group(all P<0.05).Further pairwise comparisons revealed a statistically significant difference in the incidence rate between Group A and Group D(P<0.05),indicating that the supine position was superior to the prone position.Conclusion The occurrence of radiation enteritis during volumetric modulated arc therapy is related to treatment position,and the supine position should be preferred.Furthermore,efforts should be made to control V40_R of the rectum below 45%to reduce the incidence of radiation enteritis.In patients with BMI≥24 kg/m^(2),adopting the supine position can significantly reduce the incidence of grade II and above radiation enteritis.