Table 1. Summary of risk factors for colorectal cancer in IBD.

Risk factor	Risk of CRC	Study design	Reference
Disease duration
Annual incidence	0.06–0.20%	Meta-analyses	14
Cumulative incidence, 20 y	2.5–8.0%	Meta-analyses	3 18
Cumulative incidence, 30 y	7.5–18.0%	Meta-analyses	3 18
Extent of inflammation
Pancolitis	SIR: 5.6–14.8	Meta-analyses	3 5
Left-sided colitis	SIR: 2.1–2.8	Meta-analyses	3 5
Primary sclerosing cholangitis	OR: 4.0	Meta-analyses	25
Pseudopolyposis	OR: 2.1–2.5	Case–controls	10 22
Family history of CRC	RR: 2.4–9.2	Case–controls	10 22

Abbreviation: CRC, colorectal cancer; IBD, inflammatory bowel disease; SIR, standardized incidence ratio.

Notes: Standardized incidence rates (SIRs) are all in comparison to general population. Odds ratios (OR) and relative risks (RR) are among IBD patients with and without each risk factor.