The Relation Of Exposure Dose-Volume-Time When Acute Radiation Proctitis Accured With Imrt External Beam Radiotherapy For Cervical Cancer

Objective:Cervical cancer were retrospectively analyzed in the process of external beam radiotherapy, the occuring time of acute radiation proctitis, exposure volume of rectum and the relationship of radiation proctitis various graded and dose volume of rectum with radiationtherapy for cervical cancer.Provide data reference for revising new diagnostic criteria of the domestic radiation proctitis.Materials and Methods:69 patients was diagnosised with locally advanced cervical cancer were enrolled from January,2011 to December 2013 in Sichuan cancer hospital.By RTOG/EORTC[19] toxicity grading standard to patients divided into 0 to 4.Dose volume of rectum and the average dose of rectum under the standard plan were evaluated with dose-volume histogram (DVH). The ANOVA test and t test were used for analyzing various grade acute radiation proctitis Dmax、Dmean、DIcc、D2cc、D40、V40 of rectum and the average dose of rectum when symptoms of acute radiation proctitis occured.Results:When symptoms of acute radiation proctitis occured, the average exposure dose of rectum was (21.34±9.03) Gy, and the median dose was 20.72Gy.The average time when symptoms of acute radiation proctitis occured was (23.06±12.01)th day, and the median time was 22th day;Compared with acute radiation proctitis grade 3-4 group, Dmax. value of rectum acute radiation proctitis grade 0、grade 2 were decreased and the value of grade 0 group was decreased than grade 1 group(F=5.268, P<0.05);Compared with radiation proctitisgrade 3-4 group, D1cc、D2cc value of rectum radiation proctitis grade 0、 grade 1、 grade 2 was decreased (F=4.893、4.406, P<0.05).Conclusion:Major occured mild and moderate of acute radiation proctitis, and the incidence of severe acute radiation proctitic is low when radiation exposure 20th day with IMRT techniques external beam radiotherapy for cervical cancer.Minimize Dmax、Dicc、D2cc of rectum while patients of cervical cancer were treated using IMRT techniques external beam radiotherapy, then reduced the incidence of radiation proctitis.