Study On The Related Factors Of Acute Radiation Rectal Injury After Radiotherapy For Gynecological Tumors

Objective One of the important components of gynecological malignant tumor treatment is pelvic radiotherapy,including external irradiation and brachytherapy,which is further subdivided into radical or palliative radiotherapy,preoperative neoadjuvant radiotherapy and postoperative adjuvant radiotherapy.With the continuous progress of radiotherapy technology,from conventional radiotherapy to the development of three-dimensional conformal radiotherapy,intensity modulated radiotherapy,stereotactic radiotherapy and other radiotherapy methods,the subsequent rate of radiotherapy complications is also decreasing,but it still cannot be completely avoided.One of the most common complications of pelvic radiotherapy is radiation rectal injury.RRI was divided into acute radiation rectal injury and chronic radiation rectal injury by 3 months after radiotherapy.Radioactive rectal injury is radiation（particle radiation radiation includes proton lines,electron lines,etc.;Electromagnetic radiation rays including gamma line,X-ray）caused by rectal mucosal inflammation,most patients with mild symptoms,after the end of radiation can mostly relieve themselves,a few patients will develop into chronic radiation rectal injury.The prolonged and repeated symptoms of RRI significantly affect the quality of life of patients.In this study,the incidence of RARI in gynecological malignant tumor patients after IMRT was observed,and the related risk factors of RARI were investigated.Methods The clinical data of 70 patients with gynecological malignant tumor who underwent radiotherapy in Chuzhou First People’s Hospital from 2020-02-01 to2022-02-28 were collected.Clinical data of patients were recorded,including:age of patients in clinical parameters,clinical stage of tumor,whether tumor surgery was performed,and treatment method（radiotherapy alone or concurrent chemoradiotherapy）;Dose volume factors:D_max,D_mean,V₃₅,V₄₀,V₄₅,V₅₀;Inflammatory indicators:NLR,PLR,LMR.The severity of RARI patients was graded according to RTOG/EORTC score,and they were divided into two groups:<Grade 2 RARI（n=38）and≥grade 2 RARI（n=32）.X²test,t test,logistic regression analysis,and nonparametric test were used for univariate analysis,and multivariate analysis was performed for statistically significant factors to explore independent risk factors for≥2 grade RARI.Finally,the ROC curve was used to find the critical value for predicting the factors related to acute radiation rectal injury.Test levelα=0.05（two-tailed）.Results During the observation period,32 cases（45.71%）of the 70 patients showed grade 2 acute radiation rectal injury,including 28 cases（40%）of grade 2,4 cases（5.7%）of grade 3 and 0 cases of grade 4.Univariate analysis showed that age was0.001,X²=13.243;For dose-volume factors,P values of D_max,D_mean,V₄₀and V₄₅were<0.001,0.009,0.010 and 0.016,and t values/Z were-4.125,-2.689,-2.670 and-2.484,respectively.The P values of PLR and LMR were 0.009 and 0.040,OR were1.012 and 1.518,respectively.Multivariate analysis showed age（P=0.019,OR=1.079,95%CI:1.013-1.150）,D_max（P=0.031,OR=1.005,95%CI:1.000-1.010）and PLR（P=0.024,OR=1.013,95%CI:1.002-1.024）was an independent risk factor for predicting grade≥2 RARI.Finally,ROC curve analysis showed that the AUC of age was 0.707,the critical value was 60.50,and 95%CI was 0.583-0.831.The AUC of D_maxwas 0.771,the critical value was 5217.35,and 95%CI was 0.661-0.882.The AUC of PLR was 0.685,the critical value was 142.66,and 95%CI was 0.557-0.813.Conclusion Age,D_max,and PLR can be used to predict≥2 grade RARI for gynecological malignancies.Among them,age>60 years,Dmax>52Gy and PLR>143 had higher risk factors for≥2 grade 2 RARI,and the difference was statistically significant.