Analysis Of CT3N0-2M0 Rectal Cancer Patients’ MRI-Staged Accuracy And Neo-adjuvant Therapy Effectiveness

ObjectivesAccurate evaluation of preoperative rectal cancer and distinct treatment standard for locally advanced rectal cancer are the difficult points in clinical work.Our study aims to analyze the accuracy of preoperative MRI of LARC patients and the effectiveness of neo-adjuvant chemo-radiotherapy for LARC patients.MethodsBetween January 2015 and December 2017,186 MRI-staged cT3N0-2M0 rectal carcinoma patients were retrospectively analyzed.All of them received surgical resection.We collected the records of age,gender,BMI,pre-therapeutic CEA and MRI,MDT conclusion,neo-adjuvant chemo-radiotherapy plan,operation note and pathological report.Results90 patients underwent neo-adjuvant therapy before operations,other 96 patients didn’t.When compared to pathological reports,the accuracy of MRI-measured cT and cN is 58.33%(56/96)and 55.91%(52/93).However,there is a radiologist who can maintain his cT and cN accuracy at 78.57%(11/14)as one of the long-time MDT attendees.Poorer differentiation of directly operative rectal malignancies is associated with higher probability of positive post-operative lymph nodes(P=0.005).And the positive rate of pN increases with worse pT stage(P=0.018).As for patients with neo-adjuvant therapy,degrading rate of ypT and ypN is 72.22%(65/90)and 78.89%(71/90)when compared with MRI-measured stage.And 20%(18/90)of patients were measured as pathological complete response after chemo-radiotherapy and surgery.MRI-measured negative perirectal vascular invasion is correlated with higher tumor degrading rate(P=0.02).The sphincter-preserving rate of low rectal carcinoma patients has been raised to 50%(17/34).Abnormal CEA declines to normal level in 88.46%(23/26)patients with neo-adjuvant therapy plus surgery,comparing to 74.07%(20/27)of patients with surgery alone.Conclusion1.Preoperative MRI-stage of LARC is not always accurate.The radiologist of MDT conference may be more experienced and accurate in MRI evaluation than other radiologists.2.Poorer differentiation of directly operative rectal malignancies is associated with higher probability of positive post-operative lymph nodes.And the positive rate of pN increases with worse pT stage.3.Neo-adjuvant chemo-radiotherapy is significantly effective for down staging of LARC,some patients reach pCR level.MRI-measured negative perirectal vascular invasion is correlated with higher tumor degrading rate.The sphincter-preserving rate of low rectal carcinoma patients has been elevated.Also,the decreasing of abnormal CEA to normal level happens more often in patients with neo-adjuvant therapy.