Acute Radiation-induced Reactions Of Cervical Cancer And Establishment Of Radiation Proctitis Model In New Zealand Rabbits

Part I Acute Radiation-induced Reactions of Cervical CancerObjective:To retrospectively analyze the occurrence of acute radiation-induced reactions and side effects in patients undergoing radical radiotherapy for cervical cancer in the Department of Oncology,Affiliated Hospital of North Sichuan Medical College,and to investigate the occurrence and influencing factors of acute radiation-induced reactions.Methods:Collect the case data of patients with cervical cancer who underwent radical radiotherapy in the Affiliated Hospital of North Sichuan Medical College from August 2018 to July 2019,follow their radiation-induced acute reactions within 3 months after the start of radiotherapy,and grade according to RTOG acute radiation injury classification criteria.The follow-up deadline is October 31,2019.According to the inclusion and exclusion criteria,a total of 76 patients were included in this study.Univariate and multivariate analysis of acute radiation injury was performed for their related responses and clinical case data.Results:Among 76 patients with cervical cancer who underwent radical radiotherapy,the incidence of acute radiation proctitis was 72.37%(55/76),of which the incidences of grade 1,2 and 3 were 32.89%(25/76),34.21%(26/76),5.26%(4/76),no grade 4 acute radiation proctitis occurred;the incidence of acute radiation cystitis was 61.84%(47/76),of which grade 1,2,and 3 were 39.47%(30/76),21.05%(16/76),and 1.32%(1/76),respectively,no grade 4 acute radiation cystitis occurred.A total of 68 patients have been through myelosuppression during the follow-up period,with a total incidence of 89.47%,of which 14 cases were grade 1(18.42%),33 cases were grade 2(43.42%),17 cases were grade 3(22.37%),and 4 cases were grade 4(5.26%).Multivariate analysis affecting acute radiation proctitis shows that rectal V40 is an independent factor(OR=4.875,95%CI:1.659-14.324)in the occurrence of acute proctitis,that is,rectal V40>50%may exacerbate the occurrence of acute radiation proctitis.Multivariate analysis affecting acute radiation cystitis shows that clinical stage is an independent factor(OR=3.006,95%CI:1.093～8.268)in the occurrence of acute cystitis,that is,the later the clinical stage at the time of initial diagnosis,the more likely it will occur..Conclusion:The incidence of acute radiation injury in patients with cervical cancer undergoing radical radiotherapy in our oncology department is basically consistent with that reported by other centers.Rectal V40 is an independent risk factor for the occurrence of acute radiation proctitis.The occurrence of radiation cystitis is closely related to clinical stage.May be related to bladder V40,V50.The occurrence of myelosuppression is affected by many factors,and further research and analysis are needed.Part Ⅱ Establishment of Radiation Enteritis Model in New Zealand RabbitsObjective:To irradiate New Zealand rabbits to establish acute radiation proctitis model and compare its characteristics,laying the foundation for further exploration of its occurrence and protection mechanismMethods:In this experiment,we used 33 New Zealand rabbits as experimental subjects,scanned CT and made plans to irradiate the specific areas of intestines with 5Gy,10Gy,15Gy,and 20Gy rays,respectively,to observe the mental state,weight,food and water intake,stool,voluntary activities,etc.,and on the 3rd and 5th day,blood was taken to check the inflammation index.After all the rabbits were killed on the 5th day,the intestinal changes of the irradiated site were observed,so were the changes under the microscope.Results:On the 3rd day after irradiation,the 15Gy group and the 20Gy group began to show decreased appetite,poor spirit,and changes in stool.On the 5th day,the 15Gy group gradually recovered.The 20Gy group’s symptoms continued to worsen and even one rabbit died.The other groups had no obvious symptoms.Rabbits in the 20Gy group showed a significant weight loss on the 5th day after radiotherapy(P<0.01),and the other groups remained basically stable.The 15Gy and 20Gy groups had different degrees of myelosuppression on the 3rd and 5th days after radiotherapy,respectively.Inhibition,in the 20Gy group,hemoglobin increased on the 5th day after radiotherapy(P<0.01).Platelets in the 5 groups had no significant changes before and after radiotherapy.Anatomical findings showed that the intestinal canals of the 5Gy and 10Gy groups showed only mild congestion and edema.The tract was intermittently congested,and the intestinal congestion in the irradiation site of the 20Gy group was obviously dark red,and some bowel segments had a tendency to necrosis and emit a foul odor;pathological changes under the microscope were significantly different between the 5 groups of rabbits(P<0.05).Increasing the radiation dose,intestinal damage was significantly worsened,and even severe systemic inflammatory reactions occurred,leading to rabbit death.Conclusion:We found that rabbits in the 5Gy and 10Gy groups reacted lightly and could self-heal in a short period of time,which was not enough to become a model of radiation enteritis;in the 20Gy group,severe anorexia,changes in bowel habits,intestinal damage,and even death occurred.It is not possible to provide a model for further research.The 15 Gy rabbits showed signs and symptoms consistent with clinical radiation enteritis,which can be considered successful.