NICOTINAMIDE FOR SKIN CANCER PREVENTION: WHAT DO THE NUMBERS SAY?
Nicotinamide is a form of vitamin B3 used to correct deficiency, including pellagra. Interest in preventing skin cancer grew from its role in cellular energy metabolism and from a phase III randomized trial, ONTRAC, which showed a preventive effect in high-risk patients. A later trial, ONTRANS, in patients with a history of organ transplantation did not confirm that result. Recently, data from almost 34,000 patients brought the topic back into focus: nicotinamide use was associated with a 14% lower risk of subsequent tumors. But a large sample does not remove systematic bias. What do these percentages mean, and are they enough for practical recommendations? The evidence and its practical implications are in our editorial note.