Recent epidemiological evidence shows that colorectal cancer (CRC) continues to occur in carriers of pathogenic mismatch repair (path_MMR) variants despite frequent colonoscopy surveillance in expert centres. This observation conflicts with the paradigm that removal of all visible polyps should prevent the vast majority of CRC in path_MMR carriers, provided the screening interval is sufficiently short and colonoscopic practice is optimal.
Our findings raise the possibility that some CRCs in path_MMR carriers may spontaneously disappear: the host immune response may not only remove CRC precursor lesions in path_MMRcarriers, but may remove infiltrating cancers as well. If confirmed, our suggested interpretation will have a bearing on surveillance policy for path_MMR carriers.
Lynch Syndrome Ireland 