MR Predictors Of Pathological Complete Response To Neoadjuvant Chemoradiotherapy In Locally Advanced Rectal Caner

Purpose To evaluate the value of morphological parameters that can be obtained conveniently by Magnetic Resonance Imaging(MRI)for predicting pathologically complete response(pCR)in patients with locally advanced rectal cancer.Materials and Methods A cohort of 101 patients was examined using MRI before and after Neoadjuvant chemoradiotherapy(nCRT).Morphological parameters including maximum tumor area(MTA),maximum tumor length(MTL)and maximum tumor thickness(MTT),as well as cylindrical approximated tumor volume(CATV),distance to anal verge(DTA),and their reduction rates were evaluated by two experienced readers independently.Results Post-nCRT MTA and MTL,reduction rates and pre-nCRT DTA were proved to be significantly different between pCR and non-pCR with the AUCs of 0.672-0.853.The sensitivity and specificity for assessing pCR were 61.1-89.9%and 59.0-80.7%respectively.No significant correlation between pre-nCRT size measurements and pCR was obtained.Conclusion The convenient morphological measurements may be useful for predicting pCR with moderate sensitivity and specificity.Combining these predictors with the aim of building diagnostic model should be explored.Purpose To evaluate the value of T2WI signal and related parameters that can be obtained by MRI for predicting pathologically complete response(pCR)after Neoadjuvant chemoradiotherapy(nCRT)in patients with locally adanved rectal cancer(LARC).Materials and Methods A cohort of 101 patients was examined using MRI before and after Neoadjuvant chemoradiotherapy(nCRT).Related parameters of T2WI tumor signal including Signal Intensity of Tumor(SIT),Signal Intensity of Tumor/Muscle(SIT/M),Signal Intensity of Tumor Reduction Rate(SITRR)and Signal Intensity of Tumor/Muscle Reduction Rate(SIT/MRR)were evaluated by two experienced readers independently.The results of the above parameters of mucinous/non-mucinous adenocarcinoma and only mucinous adenocarcinoma were analyzed statistically.Results SITpost and SIT/Mpost SITRR and SIT/MRR were proved to be significantly different between pCR and non-pCR before and after exclusion of mucinous adenocarcinoma.The ROC-AUCs of mucinous adenocarcinoma and non-mucinous adenocarcinoma for pCR prediction were 0.694-0.762 and 0.704-0.764 respectively.The corresponding sensitivity and specificity for pCR assessment were 66.2%-78.9%and 63.6%-84.2%respectively.No significant correlation between pre-nCRT T2WI signal related parameters and pCR was obtained.Conclusion T2WI signal related parameters,including post-nCRT signal of tumor(SITpost),signal intensity of tumor/muscle(SITfM),signal intensity of tumor reduction rate(SITRR)and signal intensity of tumor/muscle reduction rate(SIT/MRR)are potential predictors for pCR.The diagnositic efficiency is better in non-mucinous adenocarcinoma than mucinous adenocarcinoma.Purpose To evaluate the diagnostic value of clinical factors and MRI image related parameters for pCR assessment independently and dependently in locally advanced rectal cancer after neodajuvant chemoradiotherapy(pCR).Materials and Methods A cohort of 84 patients with locally anvanced recatal cancer was examined using MRI before and after Neoadjuvant chemoradiotherapy(nCRT).Clinical factors and morphological parameters including sex,age,carcino-embryonic antigen(CEA),maximum tumor area(MTA),maximum tumor length(MTL),maximum tumor thickness(MTT),cylindrical approximated tumor volume(CATV),distance to verge(DTA),signal intensity of tumor(SIT),signal Intensity of muisde(SIT/M),extramural vascular invasion(EMVI),mesorectal fascia(MRF),tumor position(TP),circumferential percentage(CP),MR tumor regression grade(MR-TRG)were evaluated by experienced readers.We calculate the reduction rate of partial indexs before and after trentment and use these parameters to establish logistic prediction pCR regression analysis model.The parameter data of 39 patients in the experimental group were subdivided into a model to verify the diagnostic value of prediction model for pCR.Results In 84 patients and 39 patients,19(22.6%)and 13(33.3%)patients achieved pCR after neoadjuvant chemoradiotherapy repectively.Maximum tumor area(MTApost),maximum tumor area reduction rate(MTARR),the maximum tumor length(MTLpost),the maximum tumor thickness(MTTpost),the maximum tumor thickness reduction rate(MTTRR),the cylindrical approximated tumor volume(CATVpost),cylindrical approximated tumor volume reduction rate(CATVRR),distance to anal verge(DTA),signal Intensity of tumor(SITpost),signal intensity of tumor teduction tate(SITRR),signal intensity of tumor/muscle(SIT/Mpost),signal intensity of tumor/muscle reduction rate(SIT/MRR)and MR-TRG were proved to be predictors for pCR in the results of univariate analysis.MTLpost,CATVpost,SITpost and the MR-TRG were proved to be independent predictors for pCR in the results of multivariate analysis.The prediction model of pCR prediction is as follow:p = ex/(l+ex),x =-11,272 + 0.476 x MTLpost －0.003 × CATVpost-0.014 x SITpost + 1.773 × MR-TRG.The area under the receiver operating curve(AUC-ROC)of the prediction model of modeling group and the validation group was 0.874 and 0.846 respectively.Conclusion MTLpost,CATVpost,SITpost and MR-TRG are independent factors of pCR,which have important clinical significance for pCR prediction.