20-MHz high-frequency endoscopic ultrasound-assisted endoscopic mucosal resection for colorectal submucosal lesions: a prospective analysis.

Goals: To prospectively assess the safety and efficacy of high-frequency ultrasound assisted mini-probe endoscopic mucosal resection for the treatment of colorectal submucosal tumors. Primary endpoints were tumor free vertical/horizontal resection margins and positive histopathologic diagnosis. Outcome data over a 24-month period were assessed.

Background: A 20-MHz high-frequency mini-probe ultrasound is an accurate modality for the diagnosis of stage T1m and T1 colorectal lesions. Few studies have addressed the safety and efficacy of this technology as applicable to submucosal lesions of the colorectum.

Methods: Thirty patients underwent high-frequency mini-probe ultrasound-guided endoscopic mucosal resection of 30 lesions (<20 mm diameter) using the inject and cut technique. Repeat endoscopy and ultrasound was performed at 3, 6, and 12 months post-"index" resection.

Results: A total of 27 lesions (90%) underwent complete resection with negative histologic margin status (median diameter, 8 mm; range, 3-20 mm). No statistical difference (P > 0.1) was observed between submucosal lesion position and histologic resection margin negativity. Three rectal lesions (10%) within the submucosal layer 3 failed to separate from the muscularis and underwent transanal excision of tumor. Bleeding occurred in 1 patient (3%). No recurrence was evident at the resection site in 27 cases (median follow-up, 9 months; range, 4-18 months).

Conclusions: High-frequency mini-probe ultrasound-guided endoscopic mucosal resection is a safe and effective therapeutic modality for submucosal lesions of the colorectum. The technique offers a single-stage diagnostic and therapeutic technique for selected submucosal lesions and may offer an alternative to surgical resection.