Resection Depth of Underwater Versus Conventional Endoscopic Mucosal Resection for Intermediate-Sized Colorectal...

Area of Science:

• Gastroenterology
• Endoscopic Surgery
• Colorectal Cancer Treatment

Background:

• Underwater endoscopic mucosal resection (UEMR) is a technique that does not involve submucosal injection.
• The comparative resection depth of UEMR versus conventional endoscopic mucosal resection (CEMR) was previously unclear.

Purpose of the Study:

• To compare the resection depth of UEMR and CEMR in patients with colorectal tumors.
• To evaluate UEMR as a potential alternative to CEMR for intermediate-sized lesions.

Main Methods:

• A noninferiority randomized controlled trial (RCT) involving 217 patients with colorectal tumors (10-20 mm).
• Patients were randomized to either UEMR or CEMR groups across four Japanese institutions.
• Resection depth was the primary outcome, analyzed per protocol with a noninferiority margin of 400 µm.

Main Results:

• Mean resection depths were 1,688.9 µm for UEMR and 1,432.3 µm for CEMR, indicating comparable depths.
• UEMR showed significantly greater resection depths in the cecum and ascending colon (P=0.01) and for superficial lesions (P<0.01).
• Nonexpert operators also achieved deeper resections with UEMR compared to CEMR (P=0.07).

Conclusions:

• UEMR provides a resection depth comparable to CEMR.
• UEMR demonstrates consistent negative horizontal margins, suggesting its potential as a gold standard for intermediate-sized colorectal tumors.