The Variation Of Gross Tumor Volume Based On Magnetic Resonance Imaging After Radiotherapy For Cervical Cancer

Background and Purpose:This study was based on magnetic resonance imaging to measure the tumor volume in each stage of radical radiotherapy for cervical cancer,To discuss the variation of tumor volume and the related factors affecting the tumor volume change.Materials and Methods:1.Cervical cancer patients with Intensity-Modulated Radiation therapy combine Three dimensional intracavitary brachytherapy which were firstly diagnosed from February2017 until August 2018 were enrolled in this study.The MRI images were import into the treatment planning system(TPS),and the tumor volume before radiotherapy,after radiotherapy(before brachetherapy),after brachetherap,3 months after brachetherapy and 6 months after brachetherapy were measured by TPS.Analyze changes in tumor volume.2.To set the original tumor volume before Intensity-Modulated Radiation therapy as 1,calculate the relative tumor volume before Intensity-Modulated Radiation therapy,after Intensity-Modulated Radiation therapy,after Brachetherapy,3 months after Brachetherapy,and 6 months after Brachetherapy respectively,The absolute tumor volume at each stage was compared.The relative tumor volume at each stage was compared..3.Analyzed the possible influencing factors which may affect tumor relative volume withdrawal rate(tumor volume withdrawal rate Grouping by median).The possible influencing factors included FIGO stage(1:IIA-IIB,2:IIIB-IVB),the original tumor volume(Grouped by 80cm~3),Lymph node metastasis(divided into two groups),Brachetherapy therapeutic dose(divided into two groups by 30Gy),anemia(divided into two groups),chemotherapy(divided into two groups).4.To utilize paired t-test to analyze the differentces of gross tumor volume between adjacent imaging examinations;Chi-square test was used for univariate analysis,Univariate analysis of general linear model was used for multivariate analysis,P<0.05statistically significant.5.Follow-up to the December 2018,According to the Radiation Therapy Oncology Organization(Radiation Therapy Oncology Group,RTOG)grading standards,evaluate the toxicity of organs at risk.Results:1.The original tumor volume is(94.34±44.03)cm~3.The tumor absolute volumes after Intensity-Modulated Radiation therapy,after Brachetherapy,3 months after Brachetherapy,and 6 months after Brachetherapy were(50.42±28.41)cm~3?(40.36±24.61)cm~3?(17.68±9.77)cm~3?(17.48±11.43)cm~3 respectively.The tumor relative volumes(based the volume as 1 before Intensity-Modulated Radiation therapy),after Intensity-Modulated Radiation therapy,after Brachetherapy,3 months after Brachetherapy,and 6 months after Brachetherapy were((0.54±0.15)?(0.44±0.15)?(0.21±0.12)?(0.20±0.13)respectively.The differences of absolute volume are compared with Paired t-test are as follows:Before Intensity-Modulated Radiation therapy and after Intensity Modulated Radiation therapy(t=9.323,P<0.001),after Intensity Modulated Radiation therapy and after Brachetherapy(t=4.766,P<0.001),after Brachetherapy and 3 months after Brachetherapy(t=4.251,P<0.001),but the differences between 3 months after Brachetherapy and 6 months after Brachetherapy have not statistical significance.The differences of relative volume are compared with Paired t-test are as follows:before Intensity Modulated Radiation therapy and after Intensity Modulated Radiation therapy(t=16.709,P<0.001),after Intensity Modulated Radiation therapy and after Brachetherapy(t=5.443,P<0.001),after Brachetherapy and3months after Brachetherapy(t=7.572,P<0.001),but the differences between 3 months after Brachetherapy and 6 months after Brachetherapyhave not statistical significance.2.Univariate analysis demonstrates FIGO stage?the original tumor volume?Lymph node metastasis?three dimensional Brachetherapy therapeutic dose,anemia and chemotherapy are no statistically significant.Multi-factor analysis results showed that FIGO stage?the original tumor volume?Lymph node metastasis?three dimensional Brachetherapy therapeutic dose,anemia and chemotherapy are no statistically significant.3.Survival analysis results(see figure 7,8,9 and 10 for details,Tumor volume was divided into two groups,large and small,with median as the boundary)Follow-up resultsThe follow-up time was 3-22 months,the median follow-up time was 12 months,and the follow-up rate was 100%,3 died and 29 survived,3 tumor progression.The median survival time was 12 months,and the survival rates at 3 months,6 months,9 months,12months,and 15 months were100%,100%,100%,96.875%,and 90.625%,respectively.Toxic side effects of organs at risk.:hematological toxicity:10 cases(31.25%)in grade 1,14 cases(43.75%)in grade 2,7 cases(21.875%)in grade 3,0cases in grade 4(0%).Grade 1-2 acute enteritis:8 cases(25%),grade 3-4 acute enteritis:0 cases(0%).Grade 1-2 acute cystitis:5(15.625%),grade 3-4 acute cystitis:0(0%).Grade 1-2 chronic enteritis:9 cases(28.12%),grade 3-4 chronic enteritis:0 cases(0%).Grade 1-2 chronic cystitis:3 cases(19.37%),grade 3-4 chronic cystitis:0 cases(0%).double lower limbs edema:3 cases(9.375%),double lower limbs no edema:29cases(90.625%),Bladder vaginal fistula:0 cases,rectal vaginal fistula:0 cases.Conclusions:Tumor volume decreased significantly before and after radiotherapy(before brachytherapy),after radiotherapy(before brachytherapy)and after brachytherapy,after brachytherapy and 3 months after brachytherapy.3 months after brachytherapy and 6 months after brachytherapy tumor volume decreased slow or stable.FIGO stage,lymph node metastasis,brachetherapy therapeutic dose,anemia,and chemotherapy may not be the influencing factors of tumor volume change.