The relationship of body mass index to setup errors, dosimetric parameters and incidence of radiation pneumonitis in non-small cell lung cancer patients undergoing intensity-modulated radiation therapy: a single-center observational study

AbstractBackground The relationship among body mass index (BMI), setup error and radiation pneumonitis is not clearly illustrated.Objective The present study aimed to investigate the role of BMI in non-small cell lung cancer (NSCLC) patients' radiation treatment, focusing on its relationship with setup error of patient positioning, the dosimetric parameters of intensity-modulated radiation therapy (IMRT) and the incidence of radiation pneumonitis.Methods This prospective observational study included 523 cases of NSCLC patients during 2020–2022. Patients were divided into different groups by different BMI. The setup error was obtained by cone beam CT (CBCT) at three positions, lateral (LAT), longitudinal (LNG) and vertical (VRT). IMRT dosimetric parameters of V5, V20, and mean dose were collected.Results Patients with BMI ≥28 kg/m2 showed significantly higher absolute values of LAT, LNG and VRT, higher V5, V20, mean dose, as well as higher total incidence of radiation pneumonitis and grade III radiation pneumonitis compared with patients with BMI <24 kg/m2 or 24–28 kg/m2. Spearman's analysis demonstrated that the absolute values of LAT, LNG and VRT were positively correlated with BMI, and positive correlation existed among BMI, dosimetric parameters and setup errors. ROC curves showed that LAT in setup errors and V5 in dosimetric parameters had the best diagnostic value for prediction of radiation pneumonitis. Only BMI, LAT, V5 and V20 were the independent risk factors for radiation pneumonitis.Conclusions Setup error caused by higher BMI might be associated with the dosimetric parameters, as well as the incidence of radiation pneumonitis in NSCLC patients.Keywords: Non-small cell lung cancerbody mass indexsetup errorsintensity-modulated radiation therapyradiation pneumonitis AcknowledgementsWe would like to give our sincere gratitude to the reviewers for their constructive comments.Ethical approvalThe use of clinical data was approved by the ethics review board of the Ethics Review Board of Wuhan Union Hospital, Huazhong University of Science and Technology.Consent formThe patients' consents for publication were obtained.Disclosure statementThe authors declare that they have no conflict of interest.Data availability statementAll data generated or analyzed during this study are included in this published article.Additional informationFundingThis work was supported by the National Natural Science Foundation of China (No. 81802287 to R Zhou).Notes on contributorsXinrui RaoXinrui Rao is a Radiation oncologist in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Hongyuan LiuHongyuan Liu is a Radiation oncology physicist in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Yuewen ZhangYuewen Zhang is a Doctoral student in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Yaqiong XieYaqiong Xie is a Radiation oncologist in Jianli People's Hospital.Geng WangGeng Wang is a Surgeon in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology and also Associate Professor; Associate Chief Physician.Sheng ZhangSheng Zhang is Chief physician in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Gang WuGang Wu is Chief physician/Professor in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology; Chief of Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Ye WangYe Wang is an Associate Senior Technologist in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Rui ZhouRui Zhou is a Radiation oncologist in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology and also an Associate Chief Physician.