Resection Depth of Underwater Versus Conventional Endoscopic Mucosal Resection for Intermediate-Sized Colorectal Tumors.
Yuzuru Tamaru, Akihiro Miyakawa, Haruhisa Shimura et al.
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In 30 seconds
This multicentre, noninferiority randomised trial compared resection depth with underwater and conventional endoscopic mucosal resection (UEMR and CEMR) for 10–20 mm colorectal tumors at four Japanese institutions. Among 217 randomly assigned patients, mean depth was 1,688.9 ± 1,510.0 μm with UEMR and 1,432.3 ± 1,294.2 μm with CEMR; the mean difference was 256.6 μm (95% confidence interval: -119.9-633.1 μm; P = 0.18). The authors concluded that UEMR achieved comparable resection depth, although the reported interval does not establish noninferiority against the prespecified margin.
Key findings
- Mean resection depth was 1,688.9 ± 1,510.0 μm with UEMR versus 1,432.3 ± 1,294.2 μm with CEMR; mean difference 256.6 μm (95% confidence interval: -119.9-633.1 μm; P = 0.18).
- For cecal and ascending-colon lesions, depth was 1,822.4 ± 1,469.7 μm with UEMR versus 1,096.5 ± 1,007.6 μm with CEMR (P = 0.01).
- For superficially shaped lesions, depth was 1,238.7 ± 862.2 μm with UEMR versus 731.6 ± 376.1 μm with CEMR (P < 0.01).
Why it matters
Resection depth is relevant to the technical adequacy of endoscopic removal. This trial provides a direct randomised comparison for intermediate-sized colorectal tumors and suggests that UEMR can achieve depths comparable to CEMR overall, with greater depths in some subgroups. The findings inform understanding of the technique but do not, by themselves, establish superiority or a change in clinical outcomes.
What to keep in mind
The primary outcome was resection depth, a procedural measure; the abstract does not report clinical outcomes such as recurrence. The confidence interval for the overall difference extends beyond the prespecified 400 μm noninferiority margin.