It is known that the development of colorectal adenoma is dependent on the appearance of somatic mutations in protooncogenes and tumor suppressor genes. Based on our previous mutation analyses of 120 patients with high-risk adenoma removed by enbloc resection with subsequent colonoscopy after 1 year, there is a correlation between mutation in exon 7 of the TP53 gene and risk of early metachronous lesions development. The results also indicate that mutation phenotype (mutation profile and burden) of all lesions detected on index colonoscopy can determine risk of metachronous lesions. As not all synchronous lesions were analyzed and the surveillance colonoscopy interval was less than 3 years, this assumption could not be confirmed. In this study it is planned to perform mutation analysis of all synchronous lesions in 200 patients and correlate the data with appearance of metachronous lesions after 1, 3 and 5 years. Moreover, the mutation profile of all metachronous lesions developed during the 5 years of surveillance will be determinated and compared with mutation profile of index lesions from the same localization to verify their common biological origin. This all could help personalize the surveillance program in terms of reduction of the burden on the patient and endoscopic workplaces and risk of developing colorectal cancer in a particular patient.