The accuracy of endoscopic ultrasound and magnetic resonance imaging for re-staging rectal cancer after neoadjuvant chemoradiation therapy

초록

Background/Aim: Endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) has been shown to be a reliable modality for staging rectal cancer. Nevertheless, the accuracy of EUS after chemoradiation remains unclear. This study aimed to compare the staging accuracy of EUS and MRI in patients with rectal cancer after neoadjuvant chemoradiation therapy. We compared EUS and MRI staging accuracy with histological findings from surgical specimens. Method: A total of 65 consecutive patients with histologically confirmed rectal cancer were examined for preoperative staging. 33 patients underwent both EUS and MRI imaging and 21 patients underwent EUS only, while 11 patients underwent MRI only after neoadjuvant chemoradiation therapy. Results: The staging accuracy of EUS based on analysis of 54 patients for T and N staging was 50% (27/54) and 57% (31/54). The accuracy of MRI based on analysis of 44 patients for T and N staging was 55% (24/44) and 36% (16/44). The accuracy of T staging was very similar for EUS and MRI for stage T2 (61% and 73%, respectively; P = 0.32) and stage T3 (65% and 59%, respectively; P = 0.71). MRI was not able to visualize most T0-T1 tumor (8/10), whereas EUS overstaged all T0 tumors (9/9). The accuracy of EUS for N staging was higher than that of MRI, although the difference did not reach statistical significance (57% and 36%, respectively; P = 0.060). Conclusions: EUS and MRI are frequently used imaging techniques for staging rectal cancer after neoadjuvant chemoradiation therapy. However, there were no significant difference in staging accuracy between EUS and MRI.