Analysis of 303 Ro/SS‐A antibody‐positive patients: is this antibody a possible marker for malignancy?

Summary Background  The risk of cancer in patients with autoimmune diseases has been investigated in several studies. Ro/SS‐A antibodies are frequent and specific autoantibodies among patients with various autoimmune diseases. Objectives  To assess the risk of cancer in individuals with positive Ro/SS‐A antibodies and to analyse their clinical and laboratory characteristics. Methods  Consecutive patients ( n  =   303) with Ro/SS‐A antibody positivity were collected during 11 years in our outpatient clinic for autoimmune diseases and were retrospectively analysed. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for all cancers were calculated. In addition, we identified further clinical and laboratory characteristics of Ro/SS‐A antibody‐positive patients indicating the development or existence of a malignancy. Results  Fifty (16·5%) patients were diagnosed with malignancies. Ro/SS‐A antibody was strongly associated with malignant diseases (SIR 2·6, 95% CI 1·9–6·1), particularly melanoma (SIR 33·3, 95% CI 5·2–188·6), T‐cell lymphoma (SIR 16·7, 95% CI 2·9–128·9), non‐Hodgkin lymphoma (SIR 10·6, 95% CI 1·5–78·9) and breast carcinoma (SIR 4·98, 95% CI 1·3–28·3). Logistic regression modelling revealed that Ro/SS‐A antibody‐positive patients aged 55 years or older, presenting with fever, anaemia and cutaneous lupus erythematosus, have a greater probability of developing cancer and are considered high‐risk patients, as compared with Ro/SS‐A antibody‐positive patients with none of the mentioned clinical criteria. Conclusions  In our cohort of Ro/SS‐A antibody‐positive patients, an overall increased risk of malignancy was noticed. Regular screening tests including imaging and laboratory values are justified in Ro/SS‐A antibody‐positive patients who exhibit the mentioned clinical criteria.