Objective To investigate the association of systemic lupus erythematosus (SLE) with cancer in the veteran population.
Background Previous studies have suggested an increased risk of cancer among patients with lupus erythematosus.
Methods and Materials A retrospective cross sectional case control study was conducted using data from the VSN 16 VA database of 484,226 VA patients, 615 (0.13%) of whom had diagnosis of systemic lupus (ICD-9 code of 710.0). Logistic regression analysis was done to adjust for covariates including age, race, and gender. Statistical tests were conducted at a 5% level of significance.
Results Diagnosis of SLE was determined to have a significant association with the diagnosis of any cancer in general and specifically skin cancer. Patients with lupus have a risk of developing cancer at 1.73 times the risk of non-lupus patients. The risk for skin cancer development among lupus patients was 1.53 times the risk of non-lupus patients. (table)
Discussion This study shows a positive correlation between lupus erythematosus and the development of cancer in the veteran population. This may reflect either decreased immune surveillance of neoplasms, increased systemic and cutaneous inflammation thus promoting gene rearrangements or increased susceptibility to neoplasm causing viral infections. Our data should be evaluated with caution, given the limitations of the population, the database and this being a case control study. However, the large size of the database was felt to limit the effect of these factors.
Conclusion Patients with SLE have an increased incidence of cancer in general and skin cancer in particular.