Value of magnetic resonance imaging in assessing the efficacy of neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Abstract

Objective To explore the clinical value of magnetic resonance imaging (MRI) for staging rectal cancer after neoadjuvant chemoradiation (Neo.CRT). Methods We retrospectively analyed the clinical data of 56 patients with rectal cancer between January 2010 and October 2015 in our hospital. MRI was performed before and after chemoradiotherapy in all patients. All patients underwent subsequent total mesorectal excision (TEM) and completed pathologic staging. The results of MRI were compared with the postoperatively pathologic staging. Results The overall accuracy of MRI for T was 78.6% (44/56), while 8 patients (14.2%) were overstaged and 4 patients (7.1%) were understaged. The sensitivity predictive values for T0, T1, T2, T3 and T4 were 66.7%, 60.0%, 78.9%, 81.8%, and 85.7%, respectively. The overall accuracy of MRI for N was 73.2% (41/56), while 9 patients (16.1%) were overstaged and 6 patients (10.7%) were understaged. The sensitivity predictive values for N0, N+ were 80.0% and 65.3%, respectively. Conclusion MRI has good accuracy in T stage and N stage diagnosis. It is one of the most common used detective methods in preoperative diagnosis of rectal cancer. Key words: Rectal cancer; Preoperative staging; Neoadjuvant chemoradiation; Magnetic resonance imaging