Possibilities of multi-parametric magnetic resonance tomography in the assessment of neoadjuvant treatment of rectal cancer

Abstract

Introduction. Modern treatment strategies of colorectal cancer determine the need for a personalized approach not only in administration of neoadjuvant therapy, but also in correction after its completion, depending on the tumor local extent and taking into account the risk of relapse. Objective. To incrise the diagnostic performance of multiparametric MRI (mpMRI) in assessing the effectiveness of treatment and predicting the clinical course of locally advanced rectal cancer (LARC) after neoadjuvant treatment. Materials and methods. 112 patients with LARC who received preoperative chemoradiotherapy (CRT) (85 patients) and CRT supplemented with neoadjuvant polychemotherapy (27 patients) followed by surgery were enrolled in retrospective study. All the patients underwent mpMRI before neoadjuvant treatment and 8-10 weeks (median 8,4 weeks) after its completion in order to evaluate the tumor response. The parameters examined included circumferential resection margin (CRM), extramural venous invasion (EMVI), T stage (T) and N stage (N), TRG (TRG). To determine the diagnostic performance of mpMRI, obtained data are compared with pathomorphology. Results. The MRI parameters with the highest diagnostic performance, in comparison with pathomorphological results, were: N stage (sensitivity 81,2%, specificity 95,6%, accuracy 91,6%), CRM (sensitivity 84%, specificity 83,9%, accuracy 83,9%) and EMVI (sensitivity 75%, specificity 85,4%, accuracy 83,9%). The diagnostic performance of T staging (sensitivity 95%, specificity 59,6%, accuracy 78,6%) and TRG (sensitivity 46%, specificity 86,3%, accuracy 72,3%) were not high enough. Conclusions. Multiparametric MRI has high sensitivity and specificity in assessing the effectiveness of neoadjuvant treatment of locally advanced rectal cancer, and that allows to choose proper patient management.