Submucosal saline injection and mini-probe endoscopic ultrasound to assess endoscopic resectability of colorectal subepithelial tumors.

BACKGROUND/AIMS: This study aimed to evaluate the feasibility and outcomes of mini-probe endoscopic ultrasound (mEUS) followed by submucosal saline injection (SSI-mEUS) for assessing the endoscopic resectability of colorectal subepithelial lesions (SELs).

METHODS

From January 2020 to December 2023, the medical records of 391 SELs (364 patients) were retrospectively reviewed and categorized into no EUS, mEUS-only, and SSI-mEUS groups according to the procedure used. To compare variables between the SSI-mEUS and other groups, the no EUS and mEUS-only groups were combined into the non-SSI-mEUS group. In the SSI-mEUS group, submucosal cushion thickness was endosonographically measured after the saline injection. Treatment outcomes and histological diagnosis were retrospectively reviewed.

RESULTS

A total of 210 lesions in the no EUS group, 23 in the mEUS-only group, and 125 in the SSI-mEUS group were endoscopically resected. The mean SEL size was larger in the SSI-mEUS than in the non-SSI-mEUS group (6.8 ± 2.6 mm vs. 4.9 ± 2.6 mm, p < 0.001). R0 resection was achieved in 107 of 110 neoplastic lesions (97.3%) in the SSI-mEUS group vs. 159 of 176 neoplastic lesions (90.3%) in the non-SSI-mEUS group (p = 0.046). Not using SSI-mEUS was the only factor associated with indeterminate or positive deep resection margins (odds ratio 3.45, 95% confidence interval 1.19-13.40, p = 0.021).

CONCLUSION

For colorectal SELs, including those that appear insufficiently elevated during conventional endoscopy, SSI-mEUS enables an objective assessment of the feasibility of endoscopic resection and can predict a high likelihood of achieving a safe and complete resection.