Roel Bogie

General discussion

but patients with LSTs may benefit from shorter surveillance intervals than patients with polypoid neoplasms.

Post-colonoscopy colorectal cancers One of the risk factors for the development of PCCRCs is inaccurate post-polypectomy surveillance. As discussed in Chapter 7 , this can be caused by both endoscopists and patient related factors. In this chapterwe reviewed themain components of different post-polypectomy surveillance guidelines and tried to subtract the most important common features. Risk assessment for new colorectal neoplasms varied and different surveillance intervals were advised between guidelines. Currently new guidelines have been published. In the Addendum of Chapter 7 an overview of the current post-polypectomy guidelines is provided, showing that follow-up strategies are still different among the most used surveillance guidelines. However, high quality index colonoscopy is a prerequisite for an adequate surveillance program. It all starts with high quality bowel preparation, high cecal intubation rates and sufficient withdrawal time, to visualize the complete colonic mucosa. 48 The use of intravenous spasmolytics and timing of the colonoscopy (planned at the first half of the program), is associated with higher adenoma detection rates. 49 A large, long term observational study showed that after single colonoscopy with high quality, the incidence rate of CRC is half of that after a colonoscopy with lesser quality. 50 New endoscopic techniques may help to further improve mucosal visualization by stretching plicae. 51 Systematic training of endoscopists on indirect signs of neoplasia (fold deformation, stool/mucus attachment, disappearing vessels, red rings) may also increase detection rates. 52 A large population-based study investigation PCCRC development within 3 years after colonoscopy, showed that prior polypectomy was a significant risk factor (RR 2.32, 95% CI: 1.97 – 2.72). 53 Risk for recurrence remains after resection of large colorectal neoplasms, especially after piecemeal resection. Therefore, follow-up colonoscopy is necessary within 6 months. 36 Chapter 7 concludes that it is the responsibility of the endoscopist to convince the patient on the need for surveillance and adhere to the requested interval. By more strict adherence and compliance, the rate of PCCRC caused by procedural errors should decrease. Optical diagnosis Recognition of subtle precursor lesions is a next step in prevention of PCCRCs. In Chapter 9 we showed that training in the detection and resection of flat neoplasms likely reduces the PCCRC prevalence. In Maastricht, systematic training on the detection of non-polypoid colorectal neoplasms had started in 2007 and comprised of lectures, training videos, feedback and supervision during colonoscopy. 24 Formation of the prospective database that has been used in Chapter 4 was started in 2008 with the aim to study non-polypoid neoplasms in more detail. Information from this database and from the National Pathology database was merged to identify PCCRCs in the period before and after starting the systematic training of endoscopists. Despite the facts that bias is likely to occur because of incomplete follow-up post-training and the assumptions made while correcting for this, the PCCRC rate was markedly lower in the post-training era. Technological improvements in quality of endoscopic imaging and in quality of bowel cleansing may also have helped to reduce PCCRC prevalence. 53 Improvements in optical diagnosis of polyps may lead to another advantage of colonoscopy. Prediction of polyp histology with high accuracy could reduce the need for histopathological analysis after resection. Diminutive hyperplastic lesions in the distal colon could even be left in situ. Such a strategy will save both time and costs, reducing the burden of screening colonoscopies.

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