Randomization and masking
tumor
TUMOR, RECRUITMENT, BLIND
Eligible patients were randomly assigned by a 1:1 ratio to either the ICG or non-ICG group. The data manager (M.L.), who was not involved in the eligibility assessment and recruitment of patients, performed randomization with a list of randomly ordered treatment identifiers generated by a permuted block design using SAS (version 9.2; SAS Institute Inc.). The allocation sequence was concealed from the surgeons who enrolled the patients until they were formally randomized to their groups. Informed consent was given to eligible patients two days before the operation. Either patients assigned to ICG or non-ICG groups, preoperative endoscopy is necessary for tumor location one day before the operation. The difference is that the ICG group received drug injections but the non-ICG group did not. Although it was not feasible to blind the surgeons and participants owing to the nature of the surgical clinical trial, the chemotherapy-treating oncologists were unaware of the intervention received by the patients.