A Preliminary Study To Evaluate The Association Between Thoracic Vertebral Insufficiency Fracture And Radiotherapy Based On Computed Tomography In Patients With Esophageal Squamous Cell Carcinoma

Objective:In this study,we used chest computed tomography(CT)to investigate whether there is an association between radiotherapy and thoracic vertebral insufficiency fracture in patients with esophageal squamous cell carcinoma,and to analyze the risk factors for thoracic vertebral insufficiency fracture.Methods:The retrospective research analyzed the clinical,imaging and follow-up data of 602 patients with pathologically confirmed esophageal squamous cell carcinoma in our hospital from March 2016 to June 2019.All patients were divided into 3 groups according to the treatment modality,119 patients received radiotherapy(RT)alone and 359 patients received chemoradiotherapy(CRT)were enrolled in the study group,124 patients without received radiotherapy(Non-RT)were enrolled in the control group.All patients received computed tomography(CT)scans of the chest before,after the radiotherapy treatment and during follow-up.We retrospectively analyzed the chest CT images of all patients to observe the treatment of tumors and obtained sagittal reconstructed images from post-processing workstations to observe whether insufficiency fractures of the thoracic vertebrae have occurred.Meanwhile,detailed clinical information was also collected from ESCC patients.The chi-square test,independent samples t-test or non-parametric rank sum test were used to compare the differences in clinical baseline information of patients between different groups,and Cox regression was used to analyze the risk factors for the occurrence of thoracic vertebral insufficiency fractures.The Kappa test was used to assess the concordance between the radiotherapy irradiation field and the thoracic fracture site in patients with radiotherapy fractures.Results:1.General information:There were 478 patients received radiotherapy,119 patients in the RT group and 359 patients in the CRT group,124 patients without received radiotherapy in the Non-RT group.The clinical baseline information such as age,sex,body mass index,smoking history and history of alcohol excess were statistically significant between the study group and the control group.Among radiotherapy patients,there was no statistically significant difference in total radiotherapy dose,radiotherapy modality,single radiotherapy dose and radiotherapy course between the RT and CRT groups.2.Risk factors for thoracic vertebral fracture:A total of 54 cases of thoracic vertebral insufficiency fractures occurred in the three groups,with a higher incidence of fractures in the RT(11.76%,14/119)and CRT groups(9.74%,35/359)than Non-RT group(4.03%,5/124).The univariable analysis revealed receiving radiotherapy[RT(HR=4.62,P=0.004),CRT(HR=3.54,P=0.009)],age(HR=1.09,P<0.001),history of alcohol excess(HR=1.88,P=0.022)and per 10 HU increase in thoracic vertebral CT values(HR=0.63,P<0.001)were associated with thoracic vertebral insufficiency fractures in patients with ESCC.While body mass index,history of smoking,clinical stage and location of the tumor had no significant correlation with thoracic fractures.The multivariable analysis showed that radiotherapy remained a risk factor for thoracic vertebral insufficiency fractures and was an independent risk factor after adjusting for age,female,history of alcohol consumption,and thoracic vertebral HU values[RT(HR=4.41,P=0.006),CRT(HR=4.40,P=0.002)].3.Radiotherapy-related factors:Further analysis of patients treated with radiotherapy revealed that the most significant factor associated with thoracic vertebral insufficiency fracture in patients with ESCC was the dose of radiotherapy,and higher doses of radiotherapy increased the risk of thoracic vertebral fracture.In addition,evaluation of thoracic vertebral bone density changes,morphological alterations and the occurrence of insufficiency fracture based on chest CT has good feasibility,the mean CT values of thoracic vertebrae in the irradiation field after radiotherapy were significantly lower than those before radiotherapy in radiotherapy patients[RT(150.63±29.65 vs.112.39±33.12,P<0.001),CRT(152.44±25.59 vs.111.38±25.61,P<0.001)],and there was a high consistency between the location of occurrence of thoracic insufficiency fractures and the range of irradiation fields for radiotherapy(κ=0.867,P<0.001).Conclusion:1.There was a correlation between thoracic vertebral insufficiency fractures and radiotherapy in ESCC patients,radiotherapy was an independent risk factor for the occurrence of thoracic insufficiency fractures,ad higher doses of radiotherapy may increase the occurrence of thoracic insufficiency fractures.In addition,there was a high concordance between the site of thoracic insufficiency fractures and the radiation field range of radiotherapy,and the CT values of thoracic vertebrae were significantly lower in patients treated with radiotherapy than before radiotherapy.2.Apart from radiotherapy factors,age,history of alcohol consumption,and thoracic vertebral CT values were associated with the occurrence of thoracic insufficiency fractures in patients with ESCC.Age and history of alcohol excess were risk factors for the occurrence of thoracic fractures.While the thoracic vertebral CT values were protective factors,the higher the thoracic vertebral CT values,the lower the incidence of thoracic vertebral fracture.3.CT could not only comprehensively assess the treatment of patients with esophageal cancer,but also observe the density and morphological changes of the thoracic spine before and after radiotherapy,which was important for the prevention,diagnosis and therapeutic evaluation of thoracic vertebral insufficiency fractures.