CT Enhancement Value Correlated With The Curative Effect Of Bevacizumab In Combination With Chemotherapy For Metastatic Colorectal Cancer

Colorectal cancer(CRC)is a common malignant tumor of the digestive system,with the third highest incidence in the world.About 50%of patients with newly diagnosed colorectal cancer present with distant metastases.For these patients with metastatic colorectal cancer(mCRC),the current treatment is comprehensive treatment which based on chemotherapy.2017 NCCN Guidelines for Colorectal Cancer recommended Bevacizumab combined with chemotherapy as standard first-line treatment for metastatic Colorectal Cancer.Microvessel density(MVD)is one of the indicators to evaluate the anti-angiogenic efficacy of bevacizumab.However,the traditional methods of evaluating MVD are invasive procedures such as biopsy and resection.Chun et al found that CT imaging was correlated with the pathological response and survival of the liver metastases of colorectal cancer patients who were treated by bevacizumab combined with chemotherapy.Therefore,we hypothesize that the level of CT enhancement was associated with the efficacy of bevacizumab in combination with chemotherapy in patients with metastatic colorectal cancer.ObjectiveThis study retrospectively analyzed the relationship between CT enhancement value and curative effect of Bevacizumab in combination with chemotherapy for metastatic colorectal cancer.Materials and MethodsThe data of patients with metastatic colorectal cancer who were admitted to Zhujiang Hospital and Southern Hospital of Southern Medical University between January 2013 and January 2018 were retrospectively analyzed.The combined group and chemotherapy group were 60 included in total.Patients in the chemotherapy group were treated with the chemotherapy regimen recommended in the 2017 NCCN guidelines for colorectal cancer(mFOLFOX6,CAPEOX,FOLFIRI).Patients in the combination group received bevacizumab(5 mg/kg)on day 1 on the basis of chemotherapy.All patients underwent CT examination within 1-2 weeks before treatment and within 6-40 weeks after treatment.Before the examination,patients should be fasted for more than 8 hours.Before and after treatment,we need to measure the average CT value during the scan and arterial phase(unit:Hu)of all the metastases included pulmonary and hepatic,and to measure its diameter before and after treatment(unit:cm),then obtained the mean value of multiple measurements.The CT enhancement value used in this study is the average CT value of arterial phase minus the one of scan phase.The preCT ?,preCT ?,postCT ?,postCT ?,CT enhancement difference value,length reduction ratio were calculated respectively.According to RECIST 1.1,CR was defined as complete disappearance of tumor,PR was defined as a reduction of tumor diameter by 30%or more,PD was defined as a increase of tumor diameter by 20%or more or found a new metastatic.And SD was defined as the one who neither met the SD standard,nor did it conform to the PD standard.The objective response rate(ORR)was(CR + PR)patients/total cases.TTP(unit:months)is defined as the time from the start of treatment to the progression or death of the disease,or the duration of disease progression to the end of follow-up.Use SPSS 21.0 software for statistical analysis.Mann-Whitney U test were used for the statistical data that did not obey the normal distribution.The data of the two matched samples were analyzed by Wilcoxon test.The Pearson X2 test Or Fisher's exact test was used to compare the clinical statics of patients in both groups.Correlation analysis was used Spearman'scorrelation model;survival curve was drawn by Kaplan-Meier method and analyzed by log-rank test.P<0.05 for the difference was statistically significant.ResultThere was no significant difference between the two groups in general conditions,including sex,primary tumor site(colon,rectum),pathological stage(poorly differentiated,moderately differentiated,well differentiated).A total of 144 lesions in 60 patients were evaluated.The CT and mCT in the combined group before and after the treatment were less than those in the chemotherapy group,which were obvious after treatment.CT difference in the combined group was significantly higher than that in the chemotherapy group(P<0.001.).The CT enhancement value,diameter and the average CT enhancement value of the combined group after treatment were significantly reduced compared with those before treatment,and the curative effect of invaded bevacizumab can be inferred by the change of CT enhancement value.The preCT was significantly negatively correlated with CT and L%in the combined group.The survival curve showed that the TTP in the combined group was longer than that in the chemotherapy group.The long-term curative effect was better in the combined group than in the chemotherapy group.In the combination group,TTP longer than low CT enhancement group,further suggesting that the value of CT enhancement with bevacizumab combined with chemotherapy in patients with metastatic colorectal cancer curative effect.Conclusion1.The curative effect of Bevacizumab combined with chemotherapy is better than chemotherapy alone,but the disease response rate has no difference.2.pre-CT in combined group was significantly correlated with CT difference value and L%,which indicated that the curative effect of bevacizumab could be reflected by the change of CT enhancement value and changes in tumor size.3.In combined group,TTP of pre-treatment high mCT group was longer than that of low CT group,which further suggested that CT enhancement was related to the curative effect of bevacizumab combined with chemotherapy in patients with metastatic colorectal cancer.