Risk of Extra-Intestinal Solid Organ Malignancy in Patients with Inflammatory Bowel Disease: A Propensity-Matched Cohort Study.

BACKGROUND: There is limited and conflicting data regarding the risk of thyroid, kidney and prostate cancer in patients with inflammatory bowel disease (IBD). METHODS: This was a retrospective cohort study using the U.S. Collaborative Network comparing the risk of thyroid, kidney and prostate cancer in the IBD compared to non-IBD (control) cohort. One-to-one propensity score matching (PSM) was performed for demographics and co-morbid conditions. Cox proportional hazard model was used to identify risk factors for each cancer. RESULTS: There were 200,280 matched pairs in the IBD and control cohort (mean age 43.7 +/- 19.5, 46.1% male, 76% White). There was an increased risk of thyroid (aOR 1.37, 95% CI 1.19-1.59), kidney (aOR 1.37, 95% CI 1.22-1.54) and prostate (aOR 1.39, 95% CI 1.29-1.151) cancer in the IBD compared to the control cohort. This was consistent based on IBD sub-type and sex. Racial/ethnic disparities were observed with respect to risk of each cancer. IBD cohort aged 18-39 was associated with increased risk (aOR 1.41, 95% CI 1.08-1.84) of thyroid but not kidney or prostate cancer compared to control cohort. Long-term steroid use was associated with an increased risk of thyroid (HR 1.92, 95% CI 1.15-3.20) and kidney (HR 1.52, 95% CI 1.25-1.86) cancer. T2DM and obesity were associated with an increased risk of all three cancers in the IBD cohort. CONCLUSION: We observed an increased risk of extra-intestinal solid organ malignancy, specifically thyroid, kidney and prostate cancer in patients with IBD.