Endoscopic submucosal dissection or transanal endoscopic microsurgery for nonpolypoid rectal high grade dysplasia and submucosa-invading rectal cancer

Background and study aims: Transanal endoscopic microsurgery (TEM) has been shown to be highly effective for early rectal cancer, and endoscopic submucosal dissection (ESD) has been introduced to treat noninvasive colorectal neoplasia. The aim of this study was to compare the outcomes of ESD and TEM for superficial early rectal cancer. Patients and methods: We retrospectively analyzed 63 patients with nonpolypoid rectal high grade dysplasia or submucosa-invading cancer who were treated with ESD or TEM, and compared clinical outcomes and safety between the treatment groups. Results: 30 patients underwent ESD and 33 underwent TEM. For ESD compared with TEM, en bloc resection rates were 96.7% vs. 100% (P=0.476) and R0 resection rates were 96.7% vs. 97.0% (P=1.000). There were no cases of local recurrence or distant metastasis in either group. Antibiotics were required in 11 patients (36.7%) in the ESD group and 33 (100%) in the TEM group (P<0.001). There was no difference in net procedure time although ESD was associated with shorter total procedure time and hospital stay than TEM, with mean (standard deviation [SD]) 84.0 (51.2) vs. 116.4 (58.5) min (P=0.0023), and 3.6 (1.2) vs. 6.6 (3.5) days (P<0.001), respectively. Therewere no significant differences in complications between the two groups. Conclusions: Both ESD and TEM are effective and oncologically safe for treating nonpolypoid rectal high grade dysplasia and submucosa-invading cancers. ESD has the additional advantages of minimal invasiveness and avoidance of anesthesia. Therefore, ESD could be recommended as a treatment option for superficial early rectal cancers.