Efficacy of Second Forward-view Examination of Left Colon for Adenoma Detection During Colonoscopy

The incidence of colorectal cancer in China is increasing year by year. Studies have shown that colorectal cancer is more common in the left colon，especially in the China. Our previous study also showed a higher rate of missed adenoma in the left colon than the right colon during colonoscopy. Additionally, prolonging withdrawal time could only improve the ADR of right colon, but had limited effect on the ADR of left colon in our previous research. Our aim is to evaluate the effect of a second forward view examination of the left colon on the detection of adenoma detection during colonoscopy.

Inclusion Criteria:Patients whose age are between 40-75, or aged 76-85 depending on his conditionPatients who have indications for screeningPatients who have signed inform consent form.Exclusion Criteria:Patients who have undergone colonic resectionPatients with alarming signs and symptoms of colorectal cancer: hematochezia, melena, anemia, weight loss, abdominal mass, positive digital rectal examinationPatients with abnormal blood coagulation or taking antiplatelets or anticoagulants within 7 days before colonoscopyPatients with inflammatory bowel diseasesPatients 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 intubationPatients with poor BPQ that necessitated a second bowel preparationPatients with therapeutic colonoscopy for existing lesionsPatients refusing to participate or to provide informed consent