18 F-FDG PET-CT In The Application Of Cervical Cancer Radiotherapy

Objective:The aim of this study was to predict prognosis in patients with locally advanced cervical cancer by the relevant parameters of 18F-fluorodeoxyglucose positron emission tomography-computed tomography(,18F-FDG PET-CT),such as maximum standardized uptake values(SUVmax),mean standardized uptake values(SUVmean),metabolic tumor volume(MTV)and total lesion glycolysis(TLG).Materials and methods:We retrospectively investigated 125 patients with locally advanced cervical cancer who underwent 18F-FDG PET-CT before definitive chemoradiotherapy in our institution from February 2010 to December 2015.SUVmax,SUVmean,MTV and TLG of the primary tumor were analyzed to evaluate the relationship between these factors and prognosis.Receiver operating characteristic(ROC)curves was used to calculate the optimal cut-off values of SUVmax,SUVmean,MTV and TLG for DFS.The survival data was analyzed by the Kaplan-Meier method and COX regression analysis.Results:The median follow-up was 29 months(range,3～77 months).Univariate analysis indicated that MTV more than or equal 18.8cm3 showed worse overall survival(OS),disease free survival(DFS)and disease metastasis free survival(DMFS).TLG more than or equal 113.5 implied worse DFS and DMFS.In multivariate analysis,TLG more than or equal 113.5 was independent predictive factor for DFS and DMFS,while there was no significant relevance for OS.Conclusion:Pretreatment TLG more than or equal 113.5 showed a higher rate of distant metastasis in patients with locally advanced cervical cancer.Objective:To compare dosimetric parameters of fixed-field intensity-modulated radiotherapy(FF-IMRT),rapid arc therapy(RA)and helical tomotherapy(HT)for extended-field irradiation in cervical cancer,aiming at investigating the suitable radiation technique.Materials and methods:We chose 15 patients with para-aortic lymph node for cervical cancer who underwent definitive chemoradiotherapy in our institution since 2015.FF-IMRT,RA and HT plans were designed basing on the same CT simulation image for each patient.To evaluate isodose distribution,conformity index(CI),homogeneity index(HI)and dose of organs at risk(OARs)by dose volume histogram(DVH)of three plans.The three plans were also compared in terms of Monitor units(MU)and time of single treatment.Results:HT showed significantly better CI and HI than FF-IMRT and RA,and RA was also superior to FF-IMRT.HT was superior to FF-IMRT and RA for protecting OARs,such as small intestine and kidney.But there was little difference between FF-IMRT and RA.RA provided shortest time of single treatment and least MU,and there was significantly difference between three plans.Conclusion:Three plans all satisfied requirement of clinical dosimetry for extended-field irradiation in cervical cancer,but HT was superior to FF-IMRT and RA.HT achieved superior OARs sparing while maintaining the best CI and HI,may reduce related toxicity of radiotherapy.RA could realize the goal of clinical dosimetry,meanwhile shorten the treatment time,probably reduce the influence of uncertain factors and patients’discomfort.