S591 Colorectal Cancer Screening Outcomes in Renal Transplant Recipients: A Single Center Retrospective Study

Introduction: Renal transplant (RT) recipients are at increased risk for various malignancies given chronic immunosuppression. Cancer screening guidelines are mostly based on the general population, including the recommendations for colon cancer screening. This raises the question of whether there is increased incidence of adenomas in the RT population and if increased frequency for colonoscopy (COL) for colorectal cancer (CRC) screening is warranted. This study aims to examine the adenoma detection rate (ADR) and CRC in RT recipients compared with the average-risk adult. Methods: We conducted a single-center retrospective cohort study of adult patients who underwent CRC screening COL post-RT from 1/2013 to 12/2023. Patients with <1 year survival post-RT, first-degree family history of CRC, or no COL reports were excluded. Primary outcomes were the incidence of precancerous polyps and CRC. Results: Among 748 RT recipients, 187 underwent post-transplant CRC screening COL and met the inclusion criteria (mean age 57.1 ± 10.2, 50% male, 38.5% White). The most common indication for RT was diabetes mellitus (21.9). Tacrolimus (85%) and mycophenolate mofetil (MMF) (68.5%) were the most commonly used immunosuppressants. Forty-five percent of RT recipients were on 3 immunosuppressant. Pre-RT COL were performed in 59.9% of patients and 51.8% of the COL had no polyps found; 84.5% of these remained negative on the first post-RT COL. The mean time from the transplant to the first COL was 45.7 ± 32.4 months. Post-RT COL findings included no polyps in 71.1%, at least 1 adenoma in 27.8%, and high-risk adenoma (HRA) in 8%. HRA included 6.4% with ≥3 polyps, 1.6% with polyps ≥10 mm, and 2.1% with villous/tubulovillous histology. Follow-up COL were performed in 8%, with 90.6% showing negative results and 1.9% identifying HRA. CRC was diagnosed in 1.1% of patients’ post-RT COL. Conclusion: Our retrospective study of RT recipients found an ADR of 27.8% and a high-risk ADR of 8%. These rates are comparable to the ADR (20%-30%) and high-risk ADR (5%-10%) reported in the literature for average-risk adults. Since there was no significant difference in ADR and high-risk ADR between average-risk adults and RT recipients, there is no indication to increase the frequency of colonoscopy intervals in RT recipients. However, larger studies with a longer period of follow up as well as a matched dataset of average-risk patients are needed to further investigate variables associated with HRA and CRC in this population.