The Multi-Society Task Force on Colorectal Cancer (MSTF) has announced that the surveillance interval for colorectal cancer (American College of Gastroenterology, American Gastroenterological Association, and American Society for Gastrointestinal Endoscopy) post-polypectomy colonoscopy has been updated from 2006. Compared to the 2006 version, the following new elements have been added: the risk of recurrence of colorectal cancer (CRC), proximal CRC, the importance of detecting serrated polyps and their role in the carcinogenic role of colorectal cancer. The key principle of the 2006 version of the guideline is the risk stratification of patients’ colonoscopy findings at baseline status. The surveillance model identifies 2 major risk groups that are at high risk of developing progressive colorectal cancer during surveillance: low-risk adenomas (LRA), defined as 1C2 tubular adenomas <10 mm in diameter. High-risk adenoma (HRA), defined as histopathologic findings of villous adenoma, high degree of dysplasia (HGD), ≥10 mm in diameter, or 3 or more adenomas. New Surveillance Intervals The key change in the 2012 guidelines is that the surveillance interval should take into account not only the patient’s most recent colonoscopy findings, but also the patient’s prior examination in which the tumor was detected by colonoscopy. Thus, patients with LRA detected at baseline colonoscopy who are not found to have a new adenoma at colonoscopy during the first surveillance period, year 5, will then be screened in the average risk population and then again during the second surveillance period, year 10. However, patients with HRA detected by colonoscopy at baseline status who were not found to have new adenomas during the first surveillance period still required a repeat colonoscopy after 5 years. Serrated polyps: The second important change in the 2012 guidelines is the emphasis on serrated polyps. 20-30% of CRCs occur from the following molecular pathway methylation genes, such as the CpG island methylation phenotype (CIMP). The precursors of this type of CRC are considered to be serrated polyps. Such CIMP-positive tumors especially in the proximal colon have a high recurrence rate during the cancer interval and therefore detection and excision of serrated adenomas has received wide attention. In addition, serrated polyp-associated colorectal cancer may be associated with inactivation of the k-ras gene and silencing of the DNA repair gene MGMT. These alterations are mainly associated with distal colorectal cancer. The guideline recommends repeat colonoscopy within 5 years in patients with small sessile serrated polyps (<10 mm) in the colorectum without dysplasia. Patients with fixed serrated polyps ≥10 mm in diameter, sessile serrated polyps with dysplasia (any size), or serrated adenomas in the traditional sense (any size) should undergo repeat colonoscopy within 3 years. Patients with serrated polyp syndrome should be followed for 1 year, although subsequent examinations have confirmed a trend toward reduction of serrated polyps and, based on these findings, the follow-up interval may be extended. Practical clinical issues: The updated guidelines also raise some practical issues that need to be addressed in daily practice. Whether surveillance for colon polyps should be discontinued, and whether both surveillance and screening should be discontinued when the risk is greater than screening. The U.S. Preventive Services Task Force (USSTF) has clarified that screening should no longer be performed in patients older than 85 because the risks may outweigh the potential benefits. the MSTF does not set an absolute age limit, but recommends that surveillance should be individualized, meaning that the benefits, risks, and co-morbidities should be evaluated before deciding whether surveillance should continue. This becomes particularly important if the patient has been free of screening colonoscopy indications. In case of poor bowel preparation before colonoscopy at baseline, regarding the timing of repeat colonoscopy, it is known that if bowel preparation before colonoscopy is inadequate, then it can mask some positive results of colonoscopy at baseline, causing the endoscopist to miss the diagnosis. Current quality indicators for colonoscopy require adequate bowel preparation with the goal of detecting adenomas >5 mm. The guidelines reiterate that there is substantial evidence that split-dose bowel preparation is more effective, and the guidelines strongly recommend this practice.The MSTF recommends that: if bowel preparation is inadequate, the examination should be repeated within 1 year in most cases. If bowel preparation is fair but sufficient to detect polyps >5 mm, and also if small LRAs are detected, the recommended interval between repeat examinations is 5 years. Aggressive fecal occult blood testing or fecal immunochemical testing prior to systematic surveillance. Routine stool chemistry testing during colonoscopy screening/monitoring is not recommended. Appropriate colonoscopy at baseline level followed by a review may determine early colonoscopy if the review results show positive fecal chemistry results. There are no study data to support the following findings: early systematic surveillance of patients improves the detection of colorectal cancer or HRAs. If the positive rate of adenoma detection remains low after colonoscopy, this suggests that there is little point in performing colonoscopy. Detection of new symptoms during the surveillance interval. New symptoms may include minor rectal bleeding, diarrhea, or constipation. After completion of the previous series, clinically significant pathologic features may be identified, but the need for a high-quality colonoscopy remains uncertain, and it is possible that performing a colonoscopy is still not meaningful. the MSTF does not believe there is sufficient evidence to make specific recommendations, and there are indications that repeat colonoscopies should be based on individualized and high clinical suspicion. Perspectives: It is clear that database evaluation of compliance with colonoscopy screening/surveillance guidelines is not optimal and leads not only to misuse of colonoscopy but also to underuse of colonoscopy. Colonoscopy would also be subject to the insurance industry. Adherence to these guidelines is defined as one of the requirements for a “good colonoscopist” and may play a role in compensating for low quality colonoscopies in the near future. Therefore, clinicians should be fully aware of these new recommendations. Although the monitoring interval after removal of a serrated polyp depends on whether an efficient colonoscopy was performed, the MSTF experts have revised the guidelines after learning of the new study data.