The Importance of Post-Inflammatory Polyps (PIPs) in Colorectal Cancer Surveillance in Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBDs), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), are chronic inflammatory disorders affecting the gastrointestinal tract. The association between IBD and colorectal cancer (CRC) is well-documented. Multiple factors have been identified as contributors to the risk of developing CRC in patients with IBD, including duration of disease, disease extension, family history of CRC, co-existance of primary sclerosing cholangitis (PSC), and potentially the presence of post-inflammatory polyps (PIPs). PIPs, often referred to as pseudopolyps, are polypoid structures that emerge as a result of severe mucosal inflammation. While their presence has been linked to greater disease severity, the role of PIPs in increasing CRC risk remains controversial. Increasing evidence suggests an association between post-inflammatory polyps (PIPs) and the risk of colorectal neoplasia, with PIPs potentially serving as an indicator of this risk through a history of enhanced inflammation. PIPs may also be linked to a distinct patient phenotype, including the presence of other known risk factors. More recent studies suggest that the risk burden (characterized by a high number or by large polyps) may be important. However, the evidence remains inconsistent, with some studies showing no clear association between PIPs and CRC risk after adjusting for other factors, including histological inflammation. In contrast, the data suggest a low rate of malignant transformation of the PIPs themselves. This narrative review aims to summarize the latest evidence regarding the relationship between PIPs and CRC in IBD, with a focus on UC. While some studies suggest that PIPs may serve as markers of higher disease severity and inflammation, their direct contribution to CRC risk remains unclear. Further research is needed to explore the inflammatory and carcinogenic pathways in patients with PIPs to better understand their role in colorectal cancer (CRC) development.