Which malignancy shows a higher standardized incidence ratio in patients with UC and PSC: biliary cancer or CRC

What is known

- With accompanying PSC, biliary cancer SIR was 10.07 (95% CI 5.75–16.36) versus 1.14 (95% CI 0.80–1.58) in UC patients overall. ¹ - Colorectal cancer incidence was not higher than the general population regardless of PSC (overall SIR 0.83; with PSC 0.73). ¹

What is unknown / caveats

- A narrative review cites prior reports of further-increased CRC risk in UC with PSC, unlike this cohort's finding of no CRC excess - Single retrospective registry (claims-based) cohort from one country - SIR of intra- plus extrahepatic biliary cancer combined was not assessable due to coding limits - No data on UC extent, CRC stage, or surveillance context; CRC patients censored at colectomy - The finding of no elevated CRC risk contrasts with prior literature and may reflect this cohort's methodology rather than a general truth.

## References

1. Oh EH, Kim YJ, Kim M, Park SH, Kim TO, Park SH. Risks of colorectal cancer and biliary cancer according to accompanied primary sclerosing cholangitis in Korean patients with ulcerative colitis: a nationwide population-based study. Intest Res. 2023. PMID: 36453007.

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_Draft, generated by the IBDology RAG and not yet clinician-reviewed. Answers are grounded in the retrieved literature listed above; a high faithfulness score means the answer matches its sources, not that the sources are correct._