Prevalence of Cancer in Rheumatoid Arthritis: Epidemiological Study Based on the National Health and Nutrition Examination Survey (NHANES).

Rheumatoid arthritis (RA) is a multi-system autoimmune disease with significant morbidity and healthcare burden. It is an inflammatory condition and has been associated with lymphomas, with or without the presence of immunosuppressive therapy. However, the association of rheumatoid arthritis with other malignancies has been inconsistent. We used the data from a population-based National Health and Nutrition Examination Survey (NHANES) for epidemiological study to evaluate the association between RA and the incidence of cancer. Using the data collected between 2011 and 2014, we were able to determine the incidence of cancer in 11,262 patients. Incidence of cancer was increased in patients with RA with an odds ratio of 1.632 (95% confidence interval [CI]: 1.239-2.151; p=0.0005). Breast cancer (CA) and prostate CA were the most common types of cancer (each diagnosed in 16.22% individuals) and lung CA and lymphomas found in 1.35% of individuals. It is also important to be aware of increased risk and adequately screen patients for malignancies during the course of treatment and follow up of rheumatoid arthritis. Further large prospective studies are required to determine the association of the RA or its treatment and the risk of malignancies.