P237 Ionising radiation exposure in patients with Crohn´s disease: estimation and risk factors
M. Barbosa*1, T. Gonçalves1, M. J. Moreira1, J. Cotter1, 2, 3
1Hospital da Senhora da Oliveira, Gastroenterology, Guimarães, Portugal, 2Instituto de Investigação em Ciências da Vida e da Saúde, Universidade do Minho, Braga, Portugal, 3Laboratório Associado ICVS/3B´s, Braga, Portugal
Patients with Crohn’s disease usually need multiple imaging studies for diagnosis, assessment of disease activity, evaluation of complications and extraintestinal manifestations, and monitoring of response to therapy. Most of these studies require ionising radiation (IR). Exposure to IR is associated with an increased risk of developing tumours.
Aims: to estimate the total dose of IR received by patients with Crohn’s disease (CD) during their course and identify the factors associated with higher radiation doses.
CD patients diagnosed between 1984 and 2013 were included. The cumulative effective dose of radiation (CEDR) was estimated for each patient collecting the number of gastrointestinal transit studies and computed tomography scans performed. CEDR was calculated multiplying the number of imaging studies by the effective dose of each examination using the standard radiation dose published. Considering recent epidemiological studies, a CEDR ≥ 50 mSv (high CEDR) was used as the cut-off point for increased risk of developing cancer.
In total, 277 patients were included: 149 (54%) female, mean age of 40 years. The mean CEDR received per patient was 33.4 mSv (0–265). Computed tomography scans accounted for 82% of the total CEDR. Further, 80 (29%) patients received a CEDR ≥ 50 mSv. Higher age (p = 0.013), longer disease duration (p = 0.001), smoking habits (p = 0.003), ileocolonic disease location (p = 0.016), stricturing/penetrating behaviour (p < 0.001), therapy with oral corticosteroids (p < 0.001), immunosuppressants (p = 0.002) and anti-TNF agents (p = 0.002), CD-related hospitalisation (p < 0.001), and need for abdominal surgery (p < 0.001) were significantly associated with a CEDR ≥ 50 mSv.
A substantial proportion of patients with CD are exposed to high doses of IR, mainly because of computed tomography scans. Identification of the patients that will most likely receive high doses of radiation, monitoring of CEDR and the use of imaging techniques that do not require IR, such as magnetic resonance imaging, abdominal ultrasound, and capsule endoscopy, could contribute to reduce patients’ exposure to potentially carcinogenic radiation.