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

The Effect of Full-time RDI on the Incidence of Major Adverse Intraoperative or Delayed Events and the Proportion of ESD Procedures With Prolonged Procedure Time: A Multicenter Prospective Randomized Controlled Trial

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 times compared to conventional WLI-guided ESD in early gastric cancer. Secondary endpoints include procedural efficiency, safety across lesion locations, and operator stress.

By rigorously assessing full-time RDI's clinical value, this study addresses an urgent unmet need to improve ESD safety and efficiency, potentially broadening its application and enhancing patient outcomes. The innovation lies in integrating continuous advanced imaging throughout ESD, representing a significant advancement in endoscopic oncology and minimally invasive gastric cancer treatment.

Inclusion Criteria:

• scheduled to undergo ESD for an early gastric cancer (the indication for ESD under current guidelines)
• both genders aged 18-75 years
• no pretreatment (ESD, surgery, radiation therapy, or chemotherapy) performed on the stomach to be examined
• platelet count of >10×10^9/L and hemoglobin count of >8.0 g/L in blood tests performed in the 3 months before the ESD
• "antithrombotic drugs" have been withdrawn for the period recommended by current guidelines
• written consent provided at the patient's discretion

Exclusion Criteria:

• scheduled for hybrid ESD
• scheduled for ESD due to multiple lesions
• scheduled for treatment of lesions with residual recurrence
• presence of submucosal tumors
• unable to discontinue an antithrombotic drugs at the time of informed consent
• inherited or acquired coagulopathy likely to affect the risk of bleeding
• receiving maintenance dialysis
• deemed unsuitable for participation in this study by the principal investigator or other investigators
• unable to provide informed consent