Journal: International journal of clinical oncology
This review focuses on intestinal neoplasia arising in the setting of ulcerative colitis (UC) and Crohn’s disease (CD), highlighting how these cancers differ from sporadic colorectal cancer in epidemiology, risk factors, pathology, and outcomes, with particular emphasis on recent Japanese multicenter data.
Key points:
- Epidemiology and risk trends
- In UC, the cumulative risk of colorectal cancer has declined in recent decades, likely due to better medical therapy and endoscopic surveillance.
- In CD, the absolute incidence of cancer is lower than in UC, but the relative risk of both colorectal and small intestinal cancer remains clearly elevated compared with the general population.
- Geographic differences are important: in East Asia, anorectal and fistula-associated carcinomas in CD are particularly prominent.
- Risk factors
- UC-associated neoplasia (UCAN):
- Long disease duration.
- Extensive colitis.
- Coexisting primary sclerosing cholangitis.
- Prior dysplasia.
- Family history of colorectal cancer.
- CD-associated neoplasia (CDAN):
- Long-standing and early-onset CD.
- Extensive colonic involvement.
- Presence of strictures.
- Family history of colorectal cancer.
- Clinicopathological features
- UCAN often appears as flat lesions with ill-defined borders, frequently with adjacent dysplasia, and commonly shows multifocal and/or infiltrative growth histologically.
- CDAN includes colorectal and small intestinal cancers, with anorectal and fistula-associated lesions being especially common in East Asian cohorts.
- Prognosis and outcomes
- Both UCAN and CDAN generally have worse survival than stage-matched sporadic colorectal cancer.
- UCAN: poorer prognosis particularly in advanced stages.
- CDAN: higher rates of local recurrence compared with sporadic colorectal cancer.
- Implications for practice
- IBD-associated neoplasia has distinct behavior and risk profiles compared with sporadic disease, mandating tailored surveillance and management.
- Large nationwide Japanese studies emphasize that region-specific data are critical to refine risk stratification, surveillance intervals, and surgical/endoscopic strategies for UC and CD patients at risk of cancer.