Endoscopic Mucosal Resection with Circumferential Mucosal Incision for Colorectal Neoplasms: Comparison with Endoscopic Submucosal Dissection and between Two Endoscopists with Different Experiences

BACKGROUND/AIMS Endoscopic mucosal resection with circumferential mucosal incision (CMI-EMR) may offer benefits comparable to those of endoscopic submucosal dissection (ESD), while requiring less technical proficiency than ESD. METHODS We retrospectively compared the outcomes of CMI-EMR (n=34) and size-matched ESD (n=102), which were performed by a Korean endoscopist for colorectal epithelial lesions of 20-35 mm. Procedural parameters of CMI-EMRs performed by an American ESD novice (n=30) were compared with those performed by the Korean endoscopist. RESULTS The lesion size was 22.3±3.9 mm and 22.9±2.4 mm in the CMI-EMR and size-matched ESD groups, respectively (p=0.730). The resection time was 12.7±7.0 minutes in the CMI-EMR group and 45.6±30.1 minutes in the ESD group (p<0.001). The en bloc resection rate was 94.1% in the CMI-EMR group and 100% in the ESD group (p=0.061). There were no differences in the en bloc resection and complication rates of CMI-EMRs between a Korean and an American endoscopist. CONCLUSIONS For the treatment of moderate-size colorectal lesions, CMI-EMR showed a trend toward lower en bloc resection rate, but required shorter procedure time than ESD. CMI-EMR outcomes were similar when performed by a Korean ESD expert and an American ESD novice.