ObjectiveTo evaluate the value of MRI with rectal water filling in the MRI T restaging following neoadjuvant chemoradiotherapy(NCRT) in rectal cancer, and determine the efficacy of NCRT.

MethodsRetrospective analysis was conducted in 39 patients with rectal cancer who were clinically diagnosed from June 2013 to June 2017, and treated with NCRT.Both before and after NCRT, MRI examination was performed after rectal water filling.The MRI stages after NCRT were compared with the postoperative pathological stages to determine the accuracy of the MRI results after treatment.Evaluation of tumor withdrawal degree and therapeutic effect after NCRT of rectal cancer based on the RECIST 1.1 standard of solid tumor evaluation.

ResultsThirty-nine patients were treated with NCRT, and compared the MRI stages before and after treatment.Of these, Twenty-nine patients had different descending stages, and their descending rate was 74.4%.There were 27 cases of postoperative pathological staging with MRI staging before and after the treatment, and the overall accuracy of MRI diagnosis was 69.2%.The MRI staging before and after NCRT was statistically significant(P < 0.01).After treatment, the tumor length and thickness were significantly reduced(P < 0.01) The overall response rate for judging the therapeutic effect of tumors according to the RECIST 1.1 standard was 53.8%.

ConclusionsMRI with rectal water filling can not only dynamically evaluate the changes of T staging before and after NCRT of rectal cancer and the changes of tumor size to effectively evaluate the efficacy, but also effectively determine the NCRT T staging, which can provide basis for surgical treatment.