Background and aims: Endoscopic submucosal dissection (ESD) has gained traction as an effective therapy for ulcerative colitis (UC)-associated dysplasia, yet identifying fitting ESD candidates is challenging by substantial submucosal (SM) fibrosis from chronic inflammation. We report our experience utilizing endoscopic ultrasonography (EUS) to assess ESD eligibility by measuring SM cushion thickness.

Methods: Retrospective case-series includes nine patients who were diagnosed with UC-associated dysplasia in surveillance colonoscopies between August 2017 and October 2023. After scanning dysplastic lesions, saline or diluted hyaluronic acid solution was injected into the SM layer. EUS with a mini-probe quantified SM cushion beneath the dysplastic lesion. Shallow (less than 2.0 mm) SM cushion at diffuse area was considered ineligible for ESD.
Results: A total of ten lesions from nine patients were evaluated before ESD. Median disease duration was 19 years, and median age at diagnosis of UC-associated dysplasia was 50 years. Median SM cushion thickness of ESD-eligible lesions was 4.2 mm at the thinnest site and 6.9 mm at the thickest site. Eight lesions met the criteria and underwent ESD, while two lesions were regarded as unsuitable for ESD due to insufficient SM cushion thickness. Median resection time was 50 minutes, and median size of resected specimens and lesions were 31.5 x 24.5 mm and 16.0 x 12.5 mm, respectively. En bloc resection was achieved in all cases, with an 87.5% (7/8) R0 resection rate. No perforation occurred but delayed bleeding occurred in one patient.

Conclusion: EUS-measured SM cushion thickness provides objective information of the lifting status after submucosal injection and may indicate the resectability of UC-associated dysplasia.

Kyuwon Kim

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