Prospective Research In Endoscopic Treatments For Diminutive And Small Colorectal Polyps

Objective:Colorectal cancer(CRC)is the third most common cancer of digestive system in China.In addition,the increasing rate of incidence of CRC has been the first among malignant tumors of the digestive system.Performing polypectomy while patients receive colonoscopy effectively can reduce the risk of CRC incidence and mortality.Over 80%～90%of colorectal polyps found during colonoscopy are diminutive or small colorectal polyps those are less than 10 mm in size.However,the optimal technique for removal of those colorectal polyps is uncertain in China.The aim of this study was to explore the best method of endoscopic treatment of diminutive and small colorectal polyps.Methods:This was a prospective randomized controlled study from the Digestive Endoscopy Center of the 900th Hospital of Joint Logistics Support Force from September 2018 to April 2019.A total of 457 patients who satisfied the inclusion criteria,polyps sized 3～10 mm,were 1:1:1 randomly assigned to the cold snare polypectomy(CSP),cold snare endoscopic mucosal resection(CS-EMR)and hot snare endoscopic mucosal resection(HS-EMR)groups.The polyps in CSP group were directly resected by cold snare,while in the other two groups,a submucosal pre-lift injection was administered prior to removal of the polyp.After submucosal injection,the polyps in CS-EMR group were resected by cold snare,while in HS-EMR group,the polyps resected by hot snare.After polypectomy,by careful observation with narrow-band imaging(NBI)at the margins and base of the polypectomy site,2-3 forceps biopsy were performed to assess the completeness of resection and all samples were sent for histopathological analysis.The primary endpoint was histologic complete resection rate of polyps;and the secondary endpionts were en-bloc resection,polypectomy procedure time,procedure-related adverse events rate(including bleeding and perforation),submucosal injection solution,the tissue retrieval rate and so on.Results:A total 457 patients with 820 polyps were assessed and randomly assigned to each group,CSP group(n=152 patients,281 polyps),CS-EMR group(n=152 patients,277 polyps)and HS-EMR group(n=153 patients,262 polyps).As for the mean size of polyp,there was no statistically significant difference in CSP group,CS-EMR group and HS-EMR group([6.77±1.76]mm vs.[7.03±1.63]mm vs.[6.82±1.50]mm;P=0.14).Patients’ characteristics(sex,age,Body Mass Index,colonoscopy indication and so on.)and polyps’ characteristics(location,size,type,pathology and so on.)in the three groups were similar.In other words,the baseline characteristics are balanced among all groups(P>0.05).The difference of complete resection rate was significantly in CSP group,CS-EMR group and HS-EMR group(83.99%vs.94.95%vs.97.71%,P<0.05).Results of further comparison showed that the CRR of CSP was lower than that of CS-EMR and HS-EMR,the difference were statistically significant(Pab=0.00;Pac=0.00);but the complete resection rate of CS-EMR and HS-EMR was similar(Pbc=0.09).And the en-bloc resection rate of CSP group was also lower than that of CS-EMR group and HS-MER group(89.32%vs.93.14%vs.96.56%,P<0.05),While the mean procedure time for polypectomy was not significantly different in the three groups([3.37±1.14]vs.[3.49±1.09]vs.[3.60±1.13]minutes;P=0.06).As for intraoperative bleeding,there were twenty-nine cases in CSP group,thirteen cases in CS-EMR group and five cases in HS-EMR group,with statistical significant difference(10.32%vs.4.69%vs.1.91%,P<0.05);and for delayed bleeding,two cases in CSP group,one case in CS-EMR group and five cases in HS-EMR group(0.71%vs.0.36%vs.1.91%,P=0.16).There was one case of intraoperative perforation in CSP group and HS-EMR group respectively;none of these patients presented with delayed perforation.There were no severe adverse events related to the biopsies,and all complications were successfully treated under endoscopy.The retrieval rate of CSP group,CS-EMR group and HS-EMR group was no significantly difference(98.60%vs.99.28%vs.98.87%,P=0.73).Results of analysis:in CS-EMR group and HS-EMR group,the CRR of diminutive and small colorectal polyps of different sizes,locations,shapes and pathological types were similar and higher,there was no statistical difference(P>0.0167).However,the complete resection rate in CSP group was lower in those polyps,the larger or located in the proximal colon,than that in CS-EMR group or HS-EMR group(P<0.0167).CS-EMR is the most satisfying of the three resection methods for endoscopists.Conclusions:Cold snare polypectomy(CSP),cold snare endoscopic mucosal resection(CS-EMR)and hot snare endoscopic mucosal resection(HS-EMR)are all effective and feasible methods for the treatment of diminutive and small colorectal polyps.Among them,the complete resection rate of large or proximal colonic polyps by CSP was slightly lower and bleeding was easy to occur during operation.Although HS-EMR had a high complete resection rate,the delayed complications were slightly higher.However,CS-EMR has a high complete resection rate for diminutive and small colorectal polyps of different sizes,locations,shapes and pathological types,and a low incidence of intraoperative and postoperative complications such as bleeding and perforation,which is an effective and safe cold resection technique for the treatment of 3-10 mm diminutive and small colorectal polyps.