Abstract:Objective To explore the diagnostic value of the combination of chromoendoscopy (CE) and narrow-band imaging (NBI) with magnifying endoscopy (ME) for early colorectal cancer and precancerous lesions.Methods 160 patients with suspected early colorectal cancer and precancerous lesions from August 2023 to July 2024 were selected. The four-grid table method was adopted to analyze the sensitivity, specificity and accuracy of NBI-ME and CE-ME in detecting early colorectal cancer and precancerous lesions. The Kappa method was used to analyze the consistency of CE-ME and NBI-ME in the diagnosis of early colorectal cancer and precancerous lesions with pathological examination.Results The pathological results showed that there were 52 cases of benign lesions, 90 cases of precancerous lesions and 18 cases of colorectal cancer. The CE-ME test results showed that there were 43 cases of benign lesions, 101 cases of precancerous lesions, and 16 cases of colorectal cancer, with a misdiagnosis rate of 33.33%. The consistency of CE-ME in diagnosing early colorectal cancer and precancerous lesions with pathological examination was average (Kappa = 0.605, P < 0.01), with a sensitivity of 66.67%, a specificity of 97.18%, and an accuracy of 93.75%. The results of NBI-ME examination showed 43 cases of benign lesions, 100 cases of precancerous lesions, and 17 cases of colorectal cancer. The misdiagnosis rate was 16.67%. The consistency of NBI-ME in diagnosing early colorectal cancer and precancerous lesions with pathological examination was relatively high (Kappa = 0.714, P < 0.01), and the sensitivity was 83.33%. The specificity was 98.59% and the accuracy was 96.88%. The combined examination results of CE-ME and NBI-ME showed that there were 56 cases of benign lesions, 86 cases of precancerous lesions, and 18 cases of colorectal cancer. The misdiagnosis rate was 5.56%. The consistency of the combined diagnosis of early colorectal cancer and precancerous lesions with pathological examination was extremely good (Kappa = 0.857, P < 0.01). The sensitivity was 94.44%, the specificity was 99.30%, and the accuracy was 98.75%, which were higher than those of CE-ME and NBI-ME alone examinations.Conclusion The combination of CE and NBI with ME has a relatively high diagnostic value for early colorectal cancer and precancerous lesions. It is worth applying in clinical practice.