9 Minutes for Tandem Colonoscopy Withdrawal

Study Overview
=================
Brief Summary
-----------------
A mean withdrawal time of at least 6 minutes has been considered to be one of the critical quality criterions of colonoscopy. Recently, our group completed a multicenter randomized controlled trial, which proved that prolonging the withdrawal time to 9 minutes could significantly improve the adenoma detection rate of colonoscopists, especially for young colonoscopists and proximal colon. However, it has some limitations in included participates (mixed indications for colonoscopy) and cannot illustrate the impact of withdrawal time on adenoma miss rate in a parallel randomized design. It is necessary to include tandem colonoscopy and adopt strict criteria of the screening population to confirm the effect of the 9-minute withdrawal time on the adenoma miss rate. Therefore, the investigators plan to conduct a multicenter, randomized controlled trial of tandem colonoscopy to compare adenoma miss rate of 6-minute and 9-minute withdrawal in screening population.

Official Title
-----------------
Impact of 9-minute Withdrawal Time on Adenoma Miss Rate: A Multicenter, Prospective, Randomized Controlled Trial of Tandem Colonoscopy

Conditions
-----------------
Colon Polyp, Colorectal Adenoma

Intervention / Treatment
-----------------
* Procedure: 6-minute then 9-minute withdrawal
* Procedure: 9-minute then 6-minute withdrawal


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients whose age is between 40-75. Patients who have indications for screening Patients who have signed inform consent form. Exclusion Criteria: Patients who have undergone colonic resection or polypectomy Patients with alarming signs and symptoms of colorectal cancer: hematochezia, melena, anemia, weight loss, abdominal mass, positive digital rectal examination Patients with abnormal blood coagulation or taking antiplatelets or anticoagulants within 7 days Patients with inflammatory bowel diseases Patients with a history of abdominal surgery, or highly suspected or confirmed colorectal cancers by radiographic and laboratory tests Patients with hereditary colorectal cancer syndrome (including familial adenomatous polyposis). Patients with pregnancy, severe chronic cardiopulmonary and renal disease. Patients with failed cecal intubation Patients with poor BPQ that necessitated a second bowel preparation Patients with therapeutic colonoscopy for existing lesions Patients refusing to participate or to provide informed consent

Ages Eligible for Study
-----------------
Minimum Age: 40 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 6-minute then 9-minute withdrawal<br>Patients in 6-minute then 9-minute withdrawal group will first be carefully observed in 6 minutes then in 9 minutes during the segmental withdrawal. At 6-minute withdrawal, the left colon, transverse colon and right colon will take 2 minutes each. Then at 9-minute withdrawal, the observation of the left colon, transverse colon and the right colon will be maintained for 3 minutes each. A stop watch will be utilized to remind endoscopists the withdrawal time. The time to perform polyp biopsy will not be included. | Procedure: 6-minute then 9-minute withdrawal<br>* Patients in 6-minute then 9-minute withdrawal group will first be carefully observed in 2 minutes then in 3 minutes during each colonic segment. In actual performance, withdrawal of the right colon, transverse colon and the left colon can be operated in segmental tandem colonoscopy. Taking the right colon as an example, after the endoscope reaches the cecum, it can be withdrawn to the splenic curvature in 2 minutes, then reentered the cecum and withdrawn to the splenic curvature in 3 minutes.<br>|
| Active Comparator: 9-minute then 6-minute withdrawal<br>Patients in 9-minute then 6-minute withdrawal group will first be carefully observed in 9 minutes then in 6 minutes during the segmental withdrawal. At 9-minute withdrawal, the left colon, transverse colon and right colon will take 3 minutes each. Then at 6-minute withdrawal, the observation of the left colon, transverse colon and the right colon will be maintained for 2 minutes each. A stop watch will be utilized to remind endoscopists the withdrawal time. The time to perform polyp biopsy will not be included. | Procedure: 9-minute then 6-minute withdrawal<br>* Patients in 9-minute then 6-minute withdrawal group will first be carefully observed in 3 minutes then in 2 minutes during each colonic segment. In actual performance, withdrawal of the right colon, transverse colon and the left colon can be operated in segmental tandem colonoscopy. Taking the right colon as an example, after the endoscope reaches the cecum, it can be withdrawn to the splenic curvature in 3 minutes, then reentered the cecum and withdrawn to the splenic curvature in 2 minutes.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| adenoma miss rate(AMR) | Adenomas detected in the second-pass examination were defined as missed adenomas; the AMR was defined as follows: number of adenomas detected in the second-pass examination/total number of adenomas detected in the two pass. | 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| advanced adenoma miss rate(AAMR) | AAMR is the number of advanced adenomas detected in the second-pass examination/total number of advanced adenomas detected in the two pass. | 60 minutes | 
| adenoma detection rate(ADR) | ADR is the number of patients with at least one adenoma, divided by the total number of patients. | 60 minutes | 
| adenomas per colonoscopy(APC) | APC was calculated as the number of adenomas detected during colonoscopy withdraw divided by the number of colonoscopies. | 60 minutes | 
| patient-level AMR(pAMR) | the number of participants with adenomas detected only during the second-pass colonoscopy divided by the total number of participants with adenomas detected during the tandem colonoscopy | 60 minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
withdrawal time, adenoma miss rate, tandem colonoscopy, adenoma detection rate