Risk of colorectal adenoma in liver transplant recipients compared to immunocompetent control population undergoing routine screening colonoscopy

BACKGROUND: Immunosuppression following solid organ transplantation has been associated with a higher prevalence of cancers including colon cancer. However, the risk of colorectal adenoma following liver transplantation is unknown. The objective of this pilot study is to determine whether the prevalence of colorectal adenoma is increased in liver transplant recipients. METHODS: In this retrospective study, 25 patients who had liver transplantation at our institution between 1994 to 1997 and who underwent routine posttransplantation colonoscopy were compared with 50 controls who were undergoing routine screening colonoscopy. Transplant recipients who were younger than 45 years, survived less than 3 years following liver transplant, with history of inflammatory bowel disease, or prior history of colonic adenoma or cancer were excluded from the study. In both groups, colonoscopic diagnosis of polyp was confirmed by pathologic diagnosis of adenoma on biopsy. RESULTS: 25 (12M/13F, mean age 53 +/- 7 years) liver transplant recipients were compared with 50 controls (19M/31F, mean age of 59 +/- 7 years). In transplant recipients, colonoscopy was performed 41 +/- 19 months after liver transplantation. Seven (28%) liver transplant recipients (5M, 2F) and 4 (8%) controls (3F, 1M) were found to have adenomatous polyp (OR 4.5, 95% CI 1-21.2, P = 0.049). Malignant polyps were not detected in both groups. CONCLUSION: Liver transplant recipients appear to have an increased risk for developing colorectal adenoma. Early screening colonoscopy is warranted for this group of patients.