Table 1.

Clinical risk factors for colitis associated colorectal cancer

Age of Onset

Increased risk among those diagnosed with IBD at a younger age (≤ 15 years)

Disease Extent

Crohn’s Disease: Increased risk when > 30–50% of colonic mucosa involved Ulcerative Colitis: 10–15 fold increased risk with pancolitis throughout disease duration, followed by 2 fold increased risk with left-sided colitis (distal to splenic flexure) until the 4th decade of disease when estimates mirror those of pancolitis, and no risk with proctitis (rectum)

Disease Duration and Severity

Risk increases with increasing disease severity (endoscopic and histology), and becomes most apparent after 7–10 years with a linear increase thereafter

Inflammatory Complications

Foreshortened colon, strictures, inflammatory pseudopolyps

Primary Sclerosing Cholangitis

Predominately right sided lesions, and increased risk present at time of diagnosis as compared to non-PSC IBD patients where risk is apparent after 7–10 years of disease duration. Increased risk remains even after liver transplant and proctocolectomy (i.e. CRC of the pouch).

Personal and Family History

Additional risk of CRC in IBD patients with a family history of CRC similar to general population. Personal history of dysplasia confers increased risk of synchronous or metachronous CRC

IBD: Inflammatory bowel disease; PSC: primary sclerosing cholangitis; CRC: colorectal cancer