Abstract
BACKGROUND & AIMS: Our understanding of malignancy associated with immunosuppression in patients with inflammatory bowel disease (IBD) comes from studies of individuals with no history of cancer. We investigated whether patients with IBD and a history of cancer who were subsequently immunosuppressed have an increased risk of developing incident cancer.
METHODS: We performed a retrospective analysis of data from 333 patients with IBD treated at 8 academic medical centers who developed cancer and subsequently received treatment with anti-tumor necrosis factor (TNF), anti-TNF with an antimetabolite (thiopurines, methotrexate), antimetabolites, or no subsequent exposure to immunosuppressive agents (controls). We collected data on their primary outcomes of incident cancers (new or recurrent). Hazard ratios (HRs) were calculated by using Cox proportional hazards and Kaplan-Meier survival curves; study groups were compared by using the log-rank test.
RESULTS: During the follow-up period, 90 patients (27%) developed an incident cancer. Patient characteristics between groups differed, but matching was not possible because of the relatively small sample sizes. There was no difference in time to incident cancer (P = .14) or type of incident cancer (P = .61) among the 4 groups. After adjusting for recurrence risk for type of prior cancer, there was no difference in risk of incident cancer (HR for anti-TNF, 0.32; 95% confidence interval [CI], 0.09-1.09; HR for anti-TNF with an antimetabolite, 0.64; 95% CI, 0.26-1.59; HR for an antimetabolite, 1.08; 95% CI, 0.54-2.15) or time to subsequent cancer between study arms (P = .22).
CONCLUSION: On the basis of a retrospective study, in patients with IBD and a history of cancer, exposure to an anti-TNF agent or an antimetabolite after cancer was not associated with an increased risk of incident cancer, compared with patients who did not receive immunosuppression. Larger, matched, prospective studies are needed to confirm these findings.