GOTHENBURG, SWEDEN – Patients with cutaneous lupus erythematosus appear to have an elevated overall risk of cancer, especially nonmelanoma skin cancer, lung cancer, and non-Hodgkin's lymphoma.
That's the preliminary conclusion from a Swedish national cohort study involving 3,788 Swedes with cutaneous LE (CLE), each matched to three controls and followed for an average of 4.1 years, said Dr. Carina M. Grönhagen at the annual congress of the European Academy of Dermatology and Venereology.
Dr. Carina Grönhagen
The take-home message from this first-ever look at the cancer risk associated with CLE is that patients with this skin disease need to be followed regularly for the emergence of malignancy. And they need to receive a strong antismoking message.
"Many of these cancers are connected to smoking, and patients with CLE are known to be smokers to a higher degree than in a normal population," observed Dr. Grönhagen, a dermatology resident at Danderyd Hospital and doctoral candidate in medical epidemiology at the Karolinska Institute, Stockholm.
She and her coworkers decided to look at cancer rates in patients with CLE because CLE is an autoimmune disease, and epidemiologic studies indicate other autoimmune diseases are associated with increased cancer risk.
The overall number of cases of cancer documented in the CLE group during the study period was 188, compared with an expected 112. This 67% increased incidence rate ratio remained significant after adjustment for comorbid SLE, which dropped the ratio only to 60%.
The greatest increase in cancer risk seen in the CLE cohort was for nonmelanoma skin cancer, with a 4.3-fold relative risk, compared with controls. The other strongest risk increases were the 2.9-fold increase in lung cancer, the 2.7-fold increase in non-Hodgkin’s lymphoma, and the 2.7-fold rise in buccal cancer.
Asked if she thinks the observed increase in cancer in association with CLE is caused by the skin disease itself, or instead perhaps the immunosuppressive therapies employed in its treatment, Dr. Grönhagen replied that the well-established high rate of smoking among CLE patients is probably a significant contributor. But the immunologic derangement inherent in CLE is also likely to play a role, especially with regard to the increase in nonmelanoma skin cancer.
Dr. Grönhagen said her presentation at the congress was an interim analysis. Assigning three controls per CLE patient is insufficient to draw ironclad conclusions. She reported that with her coworkers, she is in the process of comparing cancer rates in the CLE cohort to those in the entire Swedish population in order to generate standardized incidence rates rather than incidence rate ratios.
She declared having no relevant financial relationships.