Twenty-nine studies from 11 different registries were included in the review. Where reported, length of follow-up ranged from 198 to 29,981 patient-years. Study quality varied. Most studies scored highly on representativeness of the exposed cohort, ascertainment of exposure and demonstration that malignancy was not present at the start of the study. Only 10 of 29 studies reported on the proportion of patients lost to follow-up.
There was no evidence for a statistically significant increase in the risk of all-site malignancy (seven studies) or for a significantly increase in risk with longer exposure to TNFi (two studies).
In patients with previous malignancies there was a higher risk of a new/recurring malignancy that was not significantly increased by exposure to TNFi (two studies).
There was a significantly increased risk of non-melanoma skin cancer (1.45, 95% CI 1.15 to 1.76; four studies) and a statistically non-significant increased risk of melanoma (1.79, 95% CI 0.92 to 2.67; two studies) associated with TNFi. There was no significant increase in the risk of lymphoma (three studies).