Water-assisted endoscopy (immersion endoscopy) has emerged as an advance in the diagnosis and treatment of gastrointestinal (GI) neoplasia. By replacing luminal gas with fluid immersion, underwater techniques alter the mechanical, optical and physical environment of the GI tract and may facilitate lesion detection and therapeutic resection. This review summarises the current role of underwater and immersion-assisted endoscopy in colorectal neoplasia, focusing on diagnostic and therapeutic applications and on emerging immersion-based techniques for advanced endoscopic resection. A narrative review of the literature was performed focusing on water-aided colonoscopy (WAC), underwater endoscopic mucosal resection (U-EMR), and the Saline-Immersion/irrigation TEchnique (SITE) applied during endoscopic submucosal dissection (ESD). WAC improves patient comfort, bowel cleanliness, adenoma detection and procedural performance. U-EMR has shown favourable outcomes in colorectal lesion resection, including shorter procedure time and lower recurrence in selected lesions. More recently, fluid immersion strategies have been explored during ESD. SITE creates a fluid-filled operative field that may improve visualisation, provide buoyancy-mediated traction and enhance electrosurgical efficiency through improved conductivity. Early studies suggest that SITE-ESD may facilitate submucosal dissection, improve patient comfort, and potentially reduce thermal injury and post-ESD adverse events. Underwater and immersion-assisted endoscopy now spans the full spectrum from colonoscope insertion to advanced resection. WAC and U-EMR are increasingly embedded in routine practice, while SITE-ESD is emerging as a valuable refinement of colorectal ESD with growing adoption. Wider adoption will depend on technical standardisation, prospective comparative studies and clearer definition of its role in contemporary practice.
Kalopitas et al. (Tue,) studied this question.