Skin cancers associated with autoimmune conditions among elderly adults

BACKGROUND: Immunosuppression is a risk factor for certain skin cancers. Autoimmune conditions can involve the skin, and may involve immunosuppressive therapies. METHODS: We conducted a population-based case-control study among elderly US adults using Surveillance, Epidemiology, and End Results-Medicare-linked data of 44,613 skin cancer cases and 178,452 frequency-matched controls. Medicare claims identified autoimmune conditions. Adjusted odds ratios (ORs) compared prevalence in cases and controls. RESULTS: The most frequent autoimmune condition was rheumatoid arthritis (2.29%), which was associated with slightly increased risk of Merkel cell carcinoma (N=1977; OR (95%CI): 1.39 (1.10-1.74)). Risk of cutaneous non-Hodgkin's lymphoma (N=2652) was increased with psoriasis (OR (95%CI): 3.20 (2.62-3.92)). Risk of Kaposi's sarcoma (N=773) was elevated with ulcerative colitis (OR (95%CI): 2.76 (1.42-5.39)), and risk of other sarcomas (N=1324) was elevated with Graves disease (2.62 (1.30-5.31)). CONCLUSIONS: These findings suggest that immune disturbances in the skin, arising from autoimmune conditions or their treatment, promote development of skin cancer.