Cancer risk in cutaneous lupus erythematosus: a population-based cohort study

Objective. Immune dysregulation associated with chronic autoimmune diseases, such as SLE, has been associated with increased cancer risk. It is unclear whether isolated cutaneous lupus erythematosus (CLE) modifies cancer risk. We estimated the cumulative incidence of cancer in a population-based CLE cohort and compared the risk with a matched non-CLE cohort. Methods. All incident cases of CLE in Olmsted County, MN, USA between 1965 and 2005 were identified and followed to December 2013. Estimates for the cumulative incidence of any cancer and skin cancer in patients with CLE were derived and compared with an age-, sex- and calendar-year-matched non-CLE cohort using Cox models. Results. There were a total of 155 patients with CLE [age at diagnosis, 48 (s.d. 16) years; 65% females; BMI, 26.3 (s.d. 7.1) kg/m(2); 40% smokers, 9% with diabetes]. During a median follow-up of 14.6 years, we observed 35 cases of incident cancer (including 10 cases of skin cancer). The cumulative 1-, 5- and 10-year incidence of any cancer after diagnosis of CLE was 1.4, 7.5 and 11.6%, respectively. Compared with matched non-CLE controls, the overall risk of malignancies was not increased in patients with CLE (smoking-adjusted hazard ratio = 1.29; 95% CI: 0.78, 2.13; P = 0.31). There was also no significant increase in risk of any skin cancer in patients with CLE (hazard ratio = 2.51; 95% CI: 0.91, 6.96; P = 0.16). Conclusion. CLE is not associated with an increased risk of any cancers, including skin cancers, compared with the general population. However, the number of events was small, limiting the power of the study.