| BACKGROUNDColorectal cancer (colon cancer, rectal cancer) is one of the common malignant tumor. In our country, the incidence and the mortality of colorectal cancer have increased significantly in recent years. And colorectal polyps especially adenoma as colorectal precancerous lesions, timely detection, early treatment is an important link to prevent it development to colorectal cancer. However missed colorectal polyps or cancers are detected during repeat colonoscopy in clinical practice. The study of polyps miss rate can help us to improve the detection rate and reduce missed diagnosis, effective in reducing morbidity and mortality of colorectal cancer.OBJECTIVETo explore the miss rate of colorectal polyps including adenomatous polyps and the relevant factors in back-to-back high-quality colonoscopy.METHODSUnder the premise of limiting withdrawal time, intestinal preparation and successful rate of appendix intubation, the patients were given the second colonoscopy after conventional colonoscopy. Sizes (diameters), colonic location, and pathological types of colorectal polyps, polyp shape and polyp number were recorded. Results of two tests were counted to calculate the missed diagnosis of colon polyps. The relationship between the obtained data and the related factors was analyzed.RESULTS1. A total462polyps were found in164patients by continuous colonoscopy, the total miss rate was17.7%, and a total186adenomatous polyps were found, the miss rate is17.3%. 2. There was obvious correlation between polyps miss rate and sizes (^=25.055, P<0.001), location (χ2=15.134, P=0.010), shape (χ2=22.901,P<0.001)and number (^2=27.738,P<0.001) of polyps. Multi-factor statistical analysis on the related factors showed that polyp size is the protective factor of missed diagnosis. The larger the polyp is, the smaller the miss rate is. Compared with the diameter≤5mm, polyps of6-10mm:(OR:0.38;95%CI:0.22-0.65), diameter>10mm:(OR:0.10;95%CI:0.02-0.43). Compared with the rectum, miss rates of sigmoid colon, the transverse colon and ascending colon were increased significantly. The miss rate was significantly higher in sessile polyps (OR:4.77;95%CI:2.34-9.72) than the pedunculated polyps. And the pathological types of polyps and miss rate were not obviously correlated.3.With the rising of the polyp diameter, the proportion of the adenomatous polyps is gradually increased, there are significant differences between the different groups (χ2=16.584,P<0.005). Polyp is good hair at the left half colon and has no obvious difference in the groups (χ2=9.952, P=9.952).4. Adenoma missed diagnosis have obvious correlation with size (χ2=19.370, P=0.000), location (χ2=27.434, P=27.434), shape (χ2=15.762, P=15.762). Compared with the diameter≤5mm, polyps of6-10mm:(OR:0.43;95%CI:0.34～0.56), diameter>10mm:(OR:0.11;95%CI:0.10-0.53). The missed diagnosis has difference in different location. From the rectum, the miss rate increase, the ascending colon has the highest miss rate. The miss rate was significantly higher in sessile adenoma (OR:OR:4.19;95%CI:2.45-9.55) than the pedunculated adenoma.CONCLUSION1. Patients with colorectal polyps have a certain degree of miss rate during continuous colonoscopy.2. Miss rate is associated with sizes, location, shape, and number of colon polyps but not significantly correlated with pathological types of polyp in back-to-back high-quality colonoscopy examination. The polyp is smaller, the higher missed diagnosis. The miss rate was significantly higher in the sigmoid colon, transverse colon, ascending colon compare with rectum. The miss rate was significantly higher in sessile polyps than the pedunculated polyps. There was no difference in the various pathological types of colon polyps missed diagnosis.3. The inflammatory polyp and hyperplastic polyp is given priority to with small polyps. Increases as polyps, adenomatous polyp proportion increase gradually. Colon polyps, generally occurs in left colon, give priority to with sigmoid colon, descending colon, transverse colon.4. The miss rate of the adenomatous polyps also related to the size, position, shape. The smaller the adenoma is, the higher missed diagnosis has. It is easy to misdiagnosis in areas such as the sigmoid colon, transverse colon. The miss rate was significantly higher in sessile than the pedunculated adenoma. |
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