Radiation Exposure to the Abdomen and Pelvis in Patients Newly Diagnosed with Inflammatory Bowel Disease

Abstract

Purpose: Patients (pts) with IBD are exposed to high dose of radiation from medical imaging. We sought to identify specific subsets of this population at risk for significant radiation exposure early in the disease course. Methods: Ocean State Crohn's and Colitis Area Registry is a prospective, population-based inception cohort of Rhode Island residents. Clinical IBD diagnoses (Crohn's disease [CD], ulcerative colitis [UC], and IBD-undetermined [IBDU]) were confirmed using NIDDK Genetics Consortium criteria. Measurements of GI specific radiation, defined as radiation exposure to abdomen or pelvis, were performed in the first 336 pts included in our cohort. Radiologic studies performed in RI were recorded, and exposure for each study was estimated. Comprehensive review was performed of demography, pathology, medical/surgical treatments, as well as date and modality of radiographic exams. The difference in GI specific radiation between patient groups was analyzed by using Wilcoxon two-sample test and Kruskal Wallis test. Results: Of the 336 pts, 207 (62%) were diagnosed with CD, 120 (36%) with UC, and nine (3%) with IBDU. One hundred forty-four (43%) IBD pts had no GI specific radiation. Average GI specific radiation dose for adult IBD pts (n=237) was 14.1 mSV. It was significantly different among adult CD, UC, and IBDU pts (17.3 vs. 9.1 vs. 22.6 mSV, p=0.01). Of these, IBDU pts had the highest radiation exposure, and UC pts had the least. Average GI specific radiation dose for pediatric IBD pts (n=99) was 5.8 mSV, which was significantly less than that of adults: 14.1 mSV (p<0.0001). IBD pediatric pts also underwent less CT scans of abdomen or pelvis than adults (mean=0.24 v. 0.95, p<0.0001). We found no significant difference in radiation exposure among pediatric CD, UC, and IBDU pts. IBD adults who underwent GI surgery (n=17) had a significantly higher radiation exposure than those who did not (25.1 v. 13.2 mSV, p=0.03). IBD adults who received biologic therapy (n=55) had significantly higher radiation dose than those who did not (20.6 v. 12.1 mSV, p=0.01). There was no significant difference in radiation exposure between pediatric pts with or without operation, and with or without biologic. Conclusion: Nearly half of newly diagnosed IBD pts did not receive any GI specific radiation. Overall, IBD adults had higher radiation dose and more CT scans than pediatric pts. Adult IBD pts with CD or IBDU had higher radiation exposure than those with UC. Finally, IBD adults having GI surgery or biologic had more radiation exposure. We speculate that this may be because of more aggressive disease and need for evaluation around surgery or starting a biologic. Further study will help clarify if subsequent radiation exposure decreases after surgery or biologic therapy. This research was supported by an industry grant from Research is funded by a contract to the Crohn's & Colitis Foundation of America (CCFA) from the Center for Disease Control and Prevention (CDC) (5U01DP000340 and 3U01DP002676).