Beyond the Intestinal Mucosa in Long-Standing Inflammatory Bowel Disease: Consequences of Chronic Inflammation and Endoscopic Approaches to Diagnosis and Management

Inflammatory bowel disease (IBD) includes Crohn’s disease (CD) and ulcerative colitis (UC), chronic immune-mediated conditions of the gastrointestinal tract characterized by alternating periods of disease activity and remission with a complex multifactorial pathogenesis. Persistent intestinal inflammation in IBD is a key driver of disease progression and is strongly associated with the development of complications such as dysplasia, colorectal cancer (CRC), intestinal strictures, and fistulas. It may also result in changes in anorectal function, identifiable and classifiable using high-resolution anorectal manometry. Histologic and endoscopic assessments are essential for the evaluation of intestinal inflammation. Cumulative inflammatory burden (CIB) is an important concept that quantifies inflammatory exposure in IBD over time by integrating the severity and duration of histologic inflammation across the disease course, highlighting the importance of long-term inflammatory activity in the development of CRC. Histologic healing may be an important therapeutic target in IBD to reduce the risk of long-term complications. In parallel, emerging precision medicine approaches aim to improve risk stratification and enable early, individualized interventions to reduce disease-related outcomes. Endoscopy also plays a fundamental role in monitoring high-risk patients and guiding treatment decisions. This review aims to characterize the main intestinal complications extending beyond the mucosa that are associated with cumulative chronic inflammation in patients with IBD, including dysplasia, CRC, strictures, fistulas, and anorectal dysfunction in an era increasingly focused on achieving complete mucosal healing. Particular attention is drawn to the significant role of persistent histologic and endoscopic inflammation in disease progression and development of complications, highlighting the specific features and associated risk factors of these disease-related outcomes. Throughout, this review emphasizes the fundamental role of endoscopy in the timely detection, monitoring, and therapeutic management of IBD-related complications, thereby reinforcing its role in comprehensive patient care.