Methotrexate in psoriatic patients with melanoma -A case-control study

Abstract

Degree Project Thesis, Programme in Medicine. TITLE: Methotrexate in psoriatic patients with melanoma -A case-control study. Abstract Introduction: Malignant melanoma is the sixth most common tumour in Sweden with a 5% annual increase in incidence the last ten years and an increase in mortality-rate. Psoriasis is a common disease effecting 1.5-2% of the population in Western countries. Methotrexate has been used to treat moderate to severe psoriasis since the 1950s. Whether Methotrexate increases the risk of developing melanoma is still under debate. Aim: The aim of the study was to evaluate if Methotrexate increases the risk of melanoma in patients with psoriasis. Method: An explorative case-control study was preformed to evaluate if there was a difference in exposure to Methotrexate in psoriatic patients with melanoma compared to psoriatic patients without melanoma. Subjects were enrolled and data was collected from medical records from the Department of Dermatology at Sahlgrenska University Hospital. A case-group of 52 subject with psoriasis and melanoma was compared to a control-group of 503 subject with psoriasis without melanoma. Fischer’s exact test was used to analyze the difference of proportion in Methotrexate treatment. Results: There was a higher tendency of Methotrexate treatment in the case-group, OR=1.39. The result was not statistically significant (p= 0.35, 95% CI 0.64-2.85) Discussion and Conclusion: The analytic result in our study indicated that there was a higher risk of being exposed to Methotrexate for the case-subjects compared to the control-subjects but the result was not statistically significant. The study failed to show a statistically significant association between Methotrexate treatment and the risk of melanoma in psoriatic patients. Further research in the area is needed. Key words: Malignant melanoma, Psoriasis, Methotrexate