Endoscopic Feature And Treatment Of Colorectal Laterally Spreading Tumors

Objective:Colorectal laterally spreading tumors(LST)represent a special subtype of colonic neoplasms,which are more than 10 mm in diameter,and prefer lateral growth to vertical growth.LSTs are associated with high risk of colorectal cancer and submucosal invasion.Moreover,LSTs are prone to be missed in colonoscopy,and technically challenging in endoscopic resection,which lead to incomplete resection and local recurrence.Therefore,the endoscopic diagnosis and treatment of LSTs are important for colorectal cancer prevention.This study observed endoscopic characteristics and treatment outcomes of LSTs,in order to provide an important basis for improving the detection rate of LST and a reference for the choice of treatment.Methods:Colorectal LSTs detected in the digestive endoscopy center of PLA Army General Hospital from Mar 2010 to May 2016 were collected retrospectively.The morphology,pit patterns,appearance under narrow band imaging(NBI),and histology were observed.The treatment method and the outcomes during follow-up were analyzed.Results:1.A total of 615 colorectal LSTs(in 551patients)were collected,accounted for 2.17% of all detected polyps during the same period.The average diameter of LSTs was 22.2 ± 14.7 mm,with the most common diameter between 10 and 20mm(66.5%).LSTs were more frequently seen in the proximal colon(55.4%).The most common subtype of LST was non-granular-flat-elevated(LST-NGF),accounted for 22.76%.Among all LSTs,the submucosal carcinoma accounted for 3.25%(20/615).And LST-NGPD had the highest risk of submucosal invasion(12/84,14.29%).The mean size of rectal LSTs was larger than the colonic LSTs(31.49±23.09 vs 20.82±9.86,p<0.05),and the rectal LSTs had higher risk of canceration than colonic LSTs(36.43% vs 14.95%,p<0.001).2.The most common pit pattern of LSTs was type IIIL(30.56%)and type IV(32.94%).The type V pit pattern,which was associated with colocrecal carcinomas,was most frequently seen in LST-GM and LST-NGF(29.11% and 41.93%,respectively).All submucosal carcinoma showed the type V pit pattern,and the accuracy of type VN for predicting submucosal invasion was 58.33%.Under NBI,4.19% of the NICE-2 type lesions and 55.56% of NICE-3 type lesions were submucosal carcinoma.3.Among 615 LSTs,343(55.77%)lesions were treated by endoscopic mucosal resection(EMR)or precutting-EMR,29(4.72%)lesions were treated by endoscopic piecemeal mucosal resection(EPMR).228(37.07%)lesions were treated by endoscopic submucosal dissection(ESD),and 15 were treated surgically.Complete resection(CR)rate was 94.80%.Among 228 ESD cases,intraprocedural bleeding,delayed bleeding and perforation occured in 56(24.57%)cases,1(4.39%)and 12(5.26%)cases respectively.The total positive surgical margin rates of endoscopic treatment(including EMR,precutting-EMR and ESD)were 4.90%(28/571).In 330 patients,follow-up data were available after endoscopic treatment,and the median follow-up period was 15 months.A total of 10 recurrence cases were observed.EPMR had the highest recurrence rate(13.79%,4/29).The recurrence rate of EMR was 1.32%(2/152).However,there was no recurrence in the cases treated by ESD in recent 3 years.Conclusions:LSTs were more frequently seen in the proximal colon.LST-NGPD had the highest risk of submucosal invasion.The mean size of rectal LSTs was larger than the colonic LSTs,and the rectal LSTs had higher risk of canceration than colonic LSTs.The pit pattern V and NICE3 indicate the large possibility of submucosal invasion.For larger ones,piecemeal resection has higher recurrence rate,the endoscopic submucosal dissection(ESD)is safe and effective treatment.