Conclusions and Future Directions
Colonoscopy is currently not as effective at preventing CRC arising from the serrated pathway compared to CRC arising via the conventional adenoma-carcinoma sequence. However, all other screening methods are less effective than colonoscopy for detection of serrated lesions. With increased understanding of the importance and appearance of serrated lesions, and improved pathological subtyping, detection of serrated lesions is likely to improve. The balance between the risks and costs of resection, and the benefits for CRC prevention remain uncertain. High-quality prospective studies are needed to inform surveillance guidelines which are currently based on low or very low-quality evidence. The recognition of a new pathway to CRC outside the traditional adenoma-carcinoma sequence gives researchers and clinicians a chance to further improve CRC prevention by optimising screening to meet this new challenge (Box 4).