Association between malignancy and methotrexate and biological disease-modifying antirheumatic drugs in patients with rheumatoid arthritis

Objective: This study was aimed at investigating the risk of malignancies in rheumatoid arthritis patients treated with methotrexate (MTX), and whether the addition of biological disease-modifying antirheumatic drugs (bDMARDs) further increases the risk of malignancies in patients receiving MTX therapy, by using data from a spontaneous adverse reaction database. Materials: Patient data from the U.S. Food and Drug Administration's Adverse Event Reporting System (FAERS) from the first quarter of 2004 to the end of 2015 were analyzed. Methods: A data subset analysis was performed to investigate whether the use of bDMARDs further increased the risk of malignancies in patients receiving MTX therapy. Results: MTX showed significant associations with all malignancies except liver cancer. bDMARDs showed significant associations with stomach cancer, colorectal cancer, prostate cancer, ovarian cancer, malignant melanoma, and lung cancer. In addition, bDMARD use increased the risk of breast, ovarian, and lung cancers in rheumatoid arthritis patients receiving MTX therapy. Conclusion: MTX use was significantly associated with various malignancies. Moreover, concomitant use of bDMARDs further increased the risk of breast, ovarian, and lung cancers in MTX-treated patients with rheumatoid arthritis.