Modified Cap-assisted Endoscopic Mucosal Resection Versus Endoscopic Submucosal Dissection For The Treatment Of Rectal Neuroendocrine Neoplasm ≤10mm:A Randomized Non-inferiority Trial

Background&AimFor the treatment of rectal neuroendocrine neoplasm(R-NEN),the recent guidelines recommend endoscopic resection of rectal neuroendocrine neoplasm≤10mm in diameter without lymph node metastasis.However,there is no consensus on which endoscopic modality should be performed.In this study,we proposed a modified cap-assisted endoscopic mucosal resection(mEMR-C)without submucosal injection compared to traditional cap-assisted endoscopic mucosal resection(EMR-C).We aimed to evaluate the safety and efficacy of mEMR-C and endoscopic submucosal dissection(ESD)for the resection of small rectal neuroendocrine neoplasm ≤10mm to provide high-quality evidence regarding optimal endoscopic management in this patient population.MethodsThis study was a single-center,prospective,randomized,non-inferiority clinical trial.A randomized non-inferiority trial comparing mEMR-C and ESD was conducted.The study aims to include 90 patients with a suspected diagnosis of rectal neuroendocrine neoplasm who were admitted to Nanfang Hospital,Southern Medical University and were randomly assigned to receive mEMR-C or ESD treatment by simple randomization.Baseline data and operation-related data of patients were collected,and follow-up was conducted at 3 days and 14 days after surgery to observe whether patients had operation-related complications.The primary outcome was histological complete resection rate.Secondary outcomes included surgical success rate,en bloc resection rate,surgical duration,complications,the length of stay,the postoperative length of stay,total hospitalization cost,surgical cost,pathological results and tumor grading.Subgroup analyses were also performed.ResultsNinety patients were enrolled and 79 patients with pathologically confirmed rectal NEN were finally analyzed,including 38 cases of mEMR-C and 41 cases of ESD.Histological complete resection rate was 97.4%in the mEMR-C group and 92.7%in the ESD group.The absolute difference of histological complete resection rate was 4.7%(two-sided 90%confidence interval,-3.3%to 12.2%;P=0.616),which confirmed that mEMR-C was non-inferior to ESD.En bloc resection and successful removal of rectal NEN were achieved in all patients.The advantages of mEMR-C over ESD included shorter surgical duration(8.89±4.58 mins vs.24.8±9.14 mins,P<0.05),lower surgical cost($815.78±$167.50 vs.$1400.40±$424.93,P<0.05)as well as hospitalization cost($2233.76±$717.70 vs.$2987.27±$871.81,P<0.05).Postoperative complications were recorded in four patients who received mEMR-C and two patients in the ESD group(10.5%vs.4.9%,P=0.509),which were all well managed using medical treatment or endoscopy.Similar findings were observed when subgroup analysis was performed.ConclusionmEMR-C is non-inferior to ESD with a similar complete resection rate for resection of rectal neuroendocrine neoplasm ≤10mm.In addition,mEMR-C had shorter procedure duration time and lower hospitalization cost.This study is expected to provide high-level evidence-based medical evidence for endoscopic treatment of rectal neuroendocrine neoplasm ≤10mm.