摘要AIM: To review the present studies on early diagnosis ofcoiorectal cancer.METHODS: The detective rate for early cancer is 1.7%-26. 1 % based on various statistical data, with much higherdetective rate in endoscopy. Since early cancer meansinvasion involved in the mucosa or submucosa, thediagnosis can only be made when the invasive depth isidentified. Pathological tissue materials from bothsurgical operation or endoscopic resection are suitable forearly cancer evaluation.RESULTS: Incidence of polyp malignancy is 1.4%～20.4%. The various constitutive proportion of polyps mayexplain the different rates. Malignant incidence is higherin adenomatous polyps, that for villous polyps can reach21 .3%-58.3%. Type Ⅱ early stage of colorectal carcinomais rarely reported in China. it is shownd that majority ofthem were not malignant, most of type lla being adenomaor hyperplasia, and llb being inflammatory and llc mightbe the isolated ulcers. The occurrence of malignancy oftype Ⅱ is far lower than that of polypoid lesion. In China,the qualitative diagnosis and classification of neoplasmgenerally adopted the WHO standard, including surgicalexcision or biopsies. There is impersonal evaluationbetween colorectal pre-malignancy and cancer. Theformer emphasizes the dysplasia of nuclei and gland,while the latter is marked with cancer invasion. Diagnosisof early stage colorectal cancer in endoscopy is made withtoo much caution which made the detective rate muchlower. Mass screening for asymptomatic subjects andfollow-up for high risk population are mainly used to findthe early stage colorectal cancer in China. Fecal occultblood test is also widely made as primary screening test,galactose oxygenase test of rectal mucus (T antigen),fecal occult albumin test are also used. The detective rateof colorectal cancer is 24-36.5 per 105 mass population.CONCLUSION: Although carcinoma associated antigen inblood or stool, microsatellite DNA instability for high riskfamilial history, molecular biology technology for stooloncogene or antioncogene, telomerase activity andexfoliative cytological examination for tumor marker, areutilized, none of them is used in mass screening by now.