Malignancy risk of anti-tumor necrosis factor alpha blockers: an overview of systematic reviews and meta-analyses.

The objective of the study is to systematically review the malignancy risk of anti-tumor necrosis factor alpha (anti-TNFα) agents. Databases of PubMed Medline, OVID EMBASE, and Cochrane Library were searched to identify published systematic reviews and meta-analyses of randomized control trials, observational studies, and case series that evaluated malignancy risk of anti-TNFα blockers. Search time duration was restricted from January 1st, 2000 to July 16th, 2015. Overview Quality Assessment Questionnaires were used to assess the quality of included reviews. Two methodology trained reviewers separately and repeatedly screened searched studies according to study selection criteria, collected data, and assessed quality. Totally, 42 reviews proved eligible with only one Cochrane review. Anti-TNFα antagonists were extensively used to treat various diseases; nevertheless, malignancy risks were most commonly described in patients with rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). In RA patients, no increased risks of breast cancer, lymphoma, and non-melanoma skin cancer were found, but if the use of anti-TNFα agents was associated with elevated risk of overall malignancy was still uncertainty. In IBD patients, the use of anti-TNFα inhibitors was not connected with enhanced risk of overall cancer. No increased cancer risk was found in other disease conditions. Twenty-nine reviews were rated as good quality, 12 as moderate, and one as poor. There are no sufficient evidences to draw the conclusion that anti-TNFα blockers have relationship with increased malignancy risk.