Submit Manuscript | http://medc rav eonline.co m Introduction Colorectal adenocarcinoma is the third most common malignant neoplasia and the third leading cause of death from cancer in men and women in the United States. Current data show that the incidence of colorectal adenocarcinoma is decreasing in developed countries but increasing in developing countries. 1 The 2018 estimates of the Bra

Abstract

Introduction Rectal cancer RC is a tumor commonly diagnosed in developing countries accounting to the considerable rates of morbi mortality The neoadjuvant therapy NT with radiotherapy and chemotherapy plays a leading role in the management of this neoplasm according to oncological results and the preservation of anal function Magnetic resonance imaging MRI is one of the main tools for the evaluation of NTresults in rectal cancer in order to manage the patient rsquo s therapy Objectives To compare the results of the MRI performed right after NTwith histopathologic findings of surgical specimens in patients with RC whom underwent radical surgery Methods This retrospective study of patients with extraperitoneal RC Whom underwent radical surgery with a total mesorectal excision TME and with the preservation of sphincter after performing an NT The selected patients underwent an pelvis MRI with an emphasis on the rectum before and after performing an NT The initial stage of the disease was detected on the first MRI and the second MRI post NT was responsible for determining the tumor rsquo s regression grade TRG and downstaging disease This TRG was compared with the estimated regression obtained by histopathology of the specimen based on Dworak TRG classification and TNM classification and trying to analyze the degree of agreement of the two methods and the occurrence of downstaging Results Most patients presented a downstaging of of thedisease after NT when compared to the initial stage Six patients achieved a complete pathological response An MRI had a sensitivity of and specificity of with Positive Predictive Value PPV Negative Predictive Value NPV and an accuracy of in estimating the TRG compared to histopathology There was no correlation between patient characteristics and pathological findings and the results of TRG Conclusion An MRI of the pelvis with an emphasis on the rectum has a high accuracy rate when evaluating patients with RC submitted to NTwith radiotherapy and quimioterapy compared with histopathology and should be used routinely in clinical practice