Risk of Non-Melanoma Skin Cancer in Connective Tissue Disease and the Impact of Immunosuppressive Therapy

The risk of skin cancer in connective tissue disease and the impact of immunosuppressive therapy on this risk has not been well studied. The objective of this study is to investigate the risk of non-melanoma skin cancer in patients with connective tissue disease and to assess the impact of immunosuppressive therapy on this risk. This is a retrospective case control cohort study of 8281 patients with connective tissue disease (systemic lupus erythematosus, Sjogren's disease and scleroderma) and 8281 age, race, and gender matched controls followed for a 5-year period between 2002-2012, who obtained their care from a large integrated multispecialty group practice in Northern California. The odds ratio for developing squamous cell skin cancer among patients with connective tissue disease was 1.47 (95% CI, 1.14-1.90) (P=0.003) while the odds ratio for developing all non-melanoma skin cancer was 1.26 (95% CI, 1.08-1.49) (P=0.005). Patients on immunosuppressive medication for at least one year had an OR of 1.69 (95% CI, 1.16-2.45) of developing non-melanoma skin cancer (P=0.006) when controlled for age, race, gender, type of connective tissue disease, smoking status, and health care utilization. Our study shows an increased risk of non-melanoma skin cancer among patients with connective tissue disease. We also note that patients on immunosuppressive therapy for at least one year had an increased incidence of non-melanoma skin cancer. Further studies are needed to confirm these findings.