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 more than 30%–50% of colonic mucosa involved
Ulcerative colitis: 10- to 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 fourth 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 y with a linear increase thereafter
Inflammatory Complications
Foreshortened colon, strictures, inflammatory pseudopolyps
PSC
Predominately right-sided lesions and increased risk present at time of diagnosis as compared with non-PSC IBD patients where risk is apparent after 7–10 y of disease duration. Increased CRC risk remains even after liver transplant and proctocolectomy (i.e., cancer 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
  • Abbreviation: CRC, colorectal cancer.