Full-time RDI for ESD: Impact on Major Adverse Events and Procedure Time

Gastric cancer remains a major global health burden, ranking fifth in incidence worldwide and disproportionately affecting Asia, with China accounting for a significant share of cases and deaths. Early detection and minimally invasive treatment are critical to improving outcomes. Endoscopic submucosal dissection (ESD) is the preferred curative approach for early gastric cancer, enabling precise, en bloc tumor resection while preserving gastric function. However, ESD is technically complex, time-consuming, and associated with risks such as intraoperative and delayed bleeding and perforation. These complications limit its widespread adoption, particularly outside East Asia. Traditional ESD relies on white light imaging (WLI), which offers limited visualization of submucosal vessels and bleeding sources. Red Dichromatic Imaging (RDI) is an emerging image-enhanced endoscopy technology that uses specific narrow-band wavelengths to enhance the contrast of deep blood vessels and active bleeding sites by exploiting hemoglobin's optical absorption characteristics. Preliminary studies indicate that RDI improves bleeding point identification, facilitates hemostasis, and reduces endoscopists' procedural stress. However, prior research applied RDI only intermittently during bleeding events, leaving its potential benefits throughout the entire ESD procedure unexplored. The "full-time RDI" concept proposes continuous use of RDI during all ESD stages-including submucosal injection, mucosal incision, dissection, and wound management-to enhance visualization of high-risk vessels, improve layer differentiation, and potentially reduce adverse events and operation time. Despite promising retrospective data, robust prospective evidence from large randomized controlled trials is lacking. This multicenter, prospective randomized controlled trial aims to evaluate whether full-course RDI reduces major intraoperative and delayed complications and decreases unexpectedly prolonged operation