2.5. Randomization and blinding
colorectal ESD, tumor
TUMOR
Patients will be randomly assigned 1:1 to undergo ESD using the S-O clip or traditional study treatment groups using a minimization method. Randomization will be performed by dynamic balancing using the minimization method, with stratification by operator experience (trainee or expert), tumor location (colon/rectum), and institution. Neither patients nor physicians will be blinded to patient allocation. Endoscopists who have performed < 40 ESD procedures will be considered trainees, whereas those who have performed > 40 ESD procedures will be considered experts. Trainees who have performed < 40 colorectal ESD procedures are required to perform at least 5 of these procedures prior to the start of the study, with gastric ESD experience not required. In addition, each experts and trainee is required to perform at least 1 colorectal ESD with the S-O clip prior to the start of the study.