RESUMO
Keratinocyte cancer (KC) is the most common cancer worldwide. It is important to analyze the actual interventions that are available for the prevention of patients with a previous history of a KC. We aim to review the existent literature to assess the efficacy and safety of interventions to prevent KC in patients with a history of previous KC. We searched clinical trials in which the main outcome was the prevention of KC in patients with a previous history of KC using the strategy published in the International Prospective Register of Systematic Reviews (PROSPERO registry), CRD42016045981. We analyzed 18 clinical trials from which eight reported a benefit with their respective intervention but had methodological flaws and a variable risk of bias. Two clinical trials (regarding celecoxib and oral supplementation with nicotinamide) seemed to have the most beneficial results reducing the incidence of KC in treated groups. However, all of the studies are highly heterogeneous, which does not allow a meta-analysis to be performed. New studies with greater epidemiological value should be conducted.