中間サイズの結腸直腸腫瘍に対する水中内視鏡的粘膜切除術と従来の同種内視鏡的粘膜切除術の切除深度の比較
Yuzuru Tamaru1, Akihiro Miyakawa2, Haruhisa Shimura2
1Department of Endoscopy, NHO Kure Medical Center and Chugoku Cancer Center, Kure, Japan.
Introduction:
Underwater endoscopic mucosal resection (UEMR) does not involve submucosal injection. Its ability to achieve sufficient resection depth comparable to that of conventional endoscopic mucosal resection (CEMR) remains unclear. This randomized controlled trial (RCT) aimed to compare UEMR and CEMR, with a specific focus on resection depth.
Methods:
In this noninferiority RCT at four Japanese institutions, patients with colorectal tumors measuring 10-20 mm were randomly assigned to the UEMR or CEMR group. The primary outcome was resection depth analyzed per protocol, with a noninferiority margin of 400 µm.
Results:
In total, 217 patients were randomly assigned to the UEMR (n = 109) or CEMR (n = 108) group. The mean resection depths were 1,688.9 ± 1,510.0 µm for UEMR and 1,432.3 ± 1,294.2 µm for CEMR, with a mean difference of 256.6 µm (95% confidence interval: -119.9 to 633.1 µm; P = 0.18). Subgroup analyses revealed that UEMR achieved significantly greater resection depths in the cecum and ascending colon (1,822.4 ± 1,469.7 µm vs. 1,096.5 ± 1,007.6 µm; P = 0.01) and in lesions with superficial morphology (1,238.7 ± 862.2 µm vs. 731.6 ± 376.1 µm; P ˂ 0.01) than CEMR. Nonexpert operators also achieved deeper resections with UEMR than with CEMR (1,786.6 ± 1,471.6 µm vs. 1,192.4 ± 1,074.7 µm; P = 0.07).
Discussion:
UEMR achieved a resection depth comparable to that of CEMR. Given its consistent negative horizontal margins, UEMR may become the gold standard for resecting intermediate-sized colorectal tumors.
