"patients with IBD taking immunosuppressants and biologic agents, and as we discussed in an earlier blog, there is a growing recognition that patients receiving thiopurines have a higher risk for skin cancers.
Dr. Long and her colleagues have looked at a database of nearly 60 million patients in a retrospective, claims-based cohort analysis.[2] They used nested cohorts, looking in particular at those patients with IBD who were on or off biologics. They found approximately 100,000 patients with IBD and used a 4:1 case-to-control ratio. about 50% of these patients had Crohn's disease and about 50% had IBD that was categorized as ulcerative colitis, with another 1000 or so uncategorized. They then looked at the relative exposure to different medications and culled those patients who had been taking thiopurines and those patients who had been taking biologic agents (the anti-TNF agents).
They found that the odds ratio [of having melanoma] was nearly 1.8 times greater in the patients who had received biologic agents than in those patients who had not received biologic agents. Results were the same for thiopurines. For patients who had received thiopurines, the odds ratio was increased about 1.88, suggesting that these 2 subsets of patients with IBD had incremental risk [of developing melanoma].
The risk was increased across all patients with IBD but it was not nearly at the level for patients who had taken either the biologics or thiopurines. The background risk was 1.29 times greater for both melanomas and nonmelanomas, so it is increased slightly, but the biologics and the thiopurines seem to add a subselect pathway -- one for melanoma and one for nonmelanoma."