Risk Factors and Clinical Outcomes in Patients with IBD with Melanoma

Background: Patients with inflammatory bowel disease (IBD) are at increased risk to develop malignant melanoma and this risk may increase with use of anti-tumor necrosis factor (TNF) therapy. Impaired survival of immunosuppressed melanoma patients is reported in transplant and rheumatology patients. This study aims to (1) identify risk factors for melanoma development in patients with IBD, (2) compare clinical characteristics of melanoma in patients with IBD to the general population, and (3) assess the influence of immunosuppressive medication on survival. Methods: We retrospectively searched the Dutch Pathology Database to identify all Dutch patients with IBD with cutaneous melanoma between January 1991 and December 2011. We then performed 2 case-control studies. To identify risk factors for melanoma development in IBD, we compared patients with IBD with melanoma to the general IBD population. To compare outcome and survival after melanoma diagnosis, we compared cases with non-IBD melanoma patients. Results: We included 304 patients with IBD with melanoma, 1800 IBD controls, and 8177 melanoma controls. IBD cases had more extensive IBD (ulcerative colitis: pancolitis: cases 44.5% versus IBD controls without melanoma 28.1%; P < 0.01; Crohn's disease: ileal and colonic disease: cases 57.9% versus controls 48.9%; P = 0.02). Despite a lower Nodes (N)-stage in patients with IBD (N1+ 8.3% versus 18.2%; P < 0.01) with comparable Tumor (T) and Metastasis (M) stages, survival was similar between groups, regardless of immunosuppressive or anti-TNF therapy. Conclusions: This study showed that IBD extent is a risk factor for melanoma development. Despite the lower N-stage in patients with IBD, we could not confirm impaired survival after melanoma in patients with IBD, regardless of anti-TNF and/or thiopurine use.