2924 Risk of Malignancy Due to Radiation Exposure in Patients With IBD

Abstract

INTRODUCTION: Diagnostic imaging is routinely used in the management of IBD and in most cases, comes at the cost of repeated radiation exposure to the patient. We aim to show correlation between increased rates of cancer in patients with IBD and increased levels of radiation exposure. It is our purpose to demonstrate that efforts should be made to assessment and monitor total radiation exposure in patients with IBD. METHODS: We used a case-control design to compare patients with cancer diagnosis cases vs No cancer diagnosis controls. Cases were a composite of 74-cancer diagnosis. Cases were obtained from Cerner Healthfacts database, including 67 hospitals, using ICD9/10 codes for cancer after radiation exposure due to CT scans identified by CPT codes (74175, 74174, 74150, 74176, 74160, 74178, 74177, and 74170) in IBD patients, while controls were randomly selected from the remaining IBD patients with CT scans. Using sociodemographic and other medical diagnoses within the database, we screened candidate variables for a multivariable regression analysis for being a case and included all variables in the regression with P < 0.10 on univariate analysis. RESULTS: Between 01/01/2010 and 12/31/2016, we identified 132 patients with cancer out of 2,768 IBD patients who had radiation exposure (4.8%). Table 1 shows indication for the cancer. Combined with 2,636 controls, our study population had an average age of 48.0 (IQR: 34-62), 86.3% were white, and 59.3% were female. The two variables with P < 0.10 on univariable comparisons were included in the final model. After adjusting for confounders, older patients, and those on higher radiation doses had increased odds for developing cancer (Table 2). Steroid use and Immunomodulatory therapy, while significant on univariable analysis, were no longer significant risk factors after adjusting for confounders. CONCLUSION: Diagnostic imaging is a vital tool used to determine disease severity, extent, and response to treatment in IBD. As the disease tends to relapse and remit, repeat diagnostic imaging is a continuous part of disease management resulting in cumulative exposure to ionizing radiation over the lifetime of a patient. Patients with IBD have an increased risk of developing colorectal and small intestinal cancers than the general population irrespective of their exposure to radiation. Our data shows that additionally, the increased burden of radiation exposure increases the rates of cancer in these patients.