Anti-TNF Therapy and Radiation Exposure in Ulcerative Colitis

Abstract

Purpose: Patients with ulcerative colitis [UC] may be exposed to radiation for evaluation of disease with inherent risks from protracted exposure. Bolder definitions of disease control have changed treatment paradigms with earlier introduction of biological therapy. Our aim was to compare the effective radiation dose prior to, a year after, and 3 years after initiating anti-TNF therapy or corticosteroid. Methods: We performed a retrospective review of UC patients treated with anti-TNF therapy (infliximab or adalimumab) or corticosteroids at our institution from 2005 to 2013. Clinical data (demographics, disease characteristics, treatment) were obtained from case notes and electronic patient records. All instances of imaging in the previous year, 1 year after, and 3 years after initiation of anti-TNF therapy were recorded. The effective and cumulative radiation doses were calculated from published tables [Royal College of Radiologists, UK]. Results: We analyzed 87 patients with ulcerative colitis (57 anti-TNF and 30 corticosteroidtreated). In the anti-TNF group, 70% were males with median age 48 years (range 25-76) and mean disease duration 9.2 years. Forty-seven percent had left-sided disease, and 53% had pancolitis. Of 30 corticosteroid-treated patients, 57% were males (median age 51 years; range 17-90; mean disease duration 7.7 years). Proctitis, left-sided disease, and pancolitis were seen in 10%, 47%, and 43%, respectively. The anti-TNF cohort had a significant reduction in the number of imaging studies (4.0 +/3.9 vs. 1.5 +/-2.9, p<0.0001) and cumulative radiation dose (4.1 +/-7.0 vs. 1.2 +/-3.9 mSv, p<0.0001) a year after treatment. The corticosteroid group had no significant change in the number of imaging studies (1.9 +/-2.0 vs. 1.3 +/-2.4, p=0.1) or cumulative radiation dose (3.2 +/-5.2 vs. 1.0 +/-3.1 mSv, p=0.5). There was a significant reduction in the median number of imaging studies in the anti-TNF cohort (three studies in the year before vs. one study in the year after) compared to the steroid cohort (one study in the year before and after) [p=0.01]. In 22 patients, after 3 years of anti-TNF, there was no significant change in the cumulative radiation dose (1.6 vs. 1.0 mSv, p=0.3) or number of imaging studies (2.7 vs.1.9, p=0.3). In the corticosteroid group, there was no significant change in the cumulative radiation dose (2.5 vs. 1.1 mSv, p=0.3) or number of imaging studies (1.6 vs. 1.7, p=0.5) at the end of 3 years. The cumulative radiation dose between the year preceding, and 3 years following, therapy showed no significant difference between the groups. Conclusion: Anti-TNF, but not corticosteroid, therapy is associated with a significant reduction in diagnostic imaging studies a year after therapy. This difference was not borne out at 3 years.