Risk Of Polyp Recurrence And Surveillance Interval After Colorectal Polypectomy

ObjectiveTo identify polyp features at baseline colonoscopy that is associated with the recurrence and analyzes the risk of recurrence after colorectal polypectomy during different time of surveillance;Estimate the likelihood of detecting high-risk colorectal polyp among average-risk patients at baseline colonoscopy.MethodsPatients underwent colorectal polypectomy and followed up with colonoscopy between 2008 and 2016 in Qingdao university were retrospectively analyzed.Patient characteristics(gender,age,smoking status,Body mass index BMI,a family history of colorectal polyp or colorectal cancer)and polyp features(size,number,anatomical site,histology)at baseline colonoscopy have been documented.We used univariate analysis and multivariate logistic regression to investigate the associations between patient characteristics,polyp features at baseline colonoscopy and the recurrence;We classified patients into three groups based on baseline colonoscopy: No-risk group(hyperplastic polyp),Low-risk group(Small(< 0.1cm)tubular adenomas),High-risk group(the number of adenomas ≥3,diameter ≥0.1cm tubular adenoma,≥25% villous component,high-grade dysplasia,noninvasive carcinomas).The rate of polyp recurrence used c2 test,Kaplan-Meier to investigate cumulative recurrence rates of High-risk group and Low-risk group;A clinical risk index employing age,sex,family history of colorectal cancer(CRC),smoking history and body mass index(BMI)may be useful for prioritizing screening with colonoscopy.We used t test and c2 test to investigate the associations between clinical variables and the presence of high-risk polyp in a selected test set,and confirmed the associations in a validation set.ResultsAmong all baseline patient and polyp characteristics considered,only 4 of them were statistically significant.Age ≥70,size>0.5 cm,the number >2 and distributed in the whole colon(P=0.00).Non-neoplastic polyps can delay polyp recurrence,while tubular adenoma,tubulovillous adenoma,low-grade dysplasia,high-grade dysplasia,non-invasive carcinoma no statistical significant(P>0.05),In multivariate models,the number of polyps at baseline was the only significant predictor for polyp recurrence(OR=2.36,95%CI:1.06-5.25),age,diameter and location of polyp were not risk factors for recurrence in multivariate models.614 patients underwent 6~87 months surveillance colonoscopy.The total recurrence rates were 58.6%,during four different surveillance intervals 6~24 months、24~36 months、36~48 months、48~87 months,the cumulative recurrence rates of High-risk group(HRG)were 60.1%,65.7%,80.7% and 83.8%,whereas,22.7%,40.0%,53.8% and 65.4% in Patient with Low-risk group(LRG).There was a significant difference between the two groups(c2=17.17,P=0.00).LRG and NRG were followed up for 36 and 48 months have no find advanced neoplasia,LRG found a polyp with partial malignant change during the follow-up of 41 months,NRG found no colon cancer.HRG were followed up for 24 months find 4.1% advanced neoplasia(11/271),(mainly for the diameter ≥1 cm tubular adenoma or containing villous components),two case of colon cancer was found during the follow-up of 57 and 87 months.In the test set showed that independent risk factors for advanced colorectal neoplasia were: age,sex,family history of colorectal cancer or polyp,cigarette smoking and Body Mass Index(≥23kg/m2)(p<0.05).We developed an index that estimated the likelihood of detecting high-risk polyp.Conclusion1.Age,size,the number of polyps,and the scattered distribution of the entire colon are the primary factors associated with recurrence in primary colonoscopy.However,the number is an independent risk factor for recurrence.Non neoplastic polyps are not easy to recurrence with other pathological types.2.The rate of polyp recurrence during surveillance was significantly increased with time prolonged.The cumulative recurrence rates after polypectomy for HRG are significantly higher than LRG at baseline.Follow up should not be more than 2 years after endoscopic polypectomy in high-risk patients,low-risk groups can be around 3 years and the no-risk group can be extended to a follow-up of 4 years is safe.3.Age,sex,family history,cigarette smoking,BMI successfully estimates the likelihood of detecting advanced colorectal neoplasia at baseline colonoscopy.