Prevention of non-melanoma skin cancers with nicotinamide in transplant recipients: A case-control study

Background: Nicotinamide is the precursor of nicotinamide adenine dinucleotide (NAD+), an essential cofactor for adenosine triphosphate (ATP) production. It has recently been reported to be effective in reducing the rates of new non-melanoma skin cancers (NMSCs) and actinic keratosis (AKs). Objectives: We studied the efficacy of oral nicotinamide as treatment for AKs in transplant recipients. Materials & methods: We recruited 38 transplant (eight liver and 30 kidney) patients with single or multiple AKs. Nineteen patients were randomly assigned to Group 1 and took nicotinamide 500 mg/daily (cases); the other 19 patients were randomly assigned to Group 2 without nicotinamide (controls). At baseline, AKs were identified, measured, and photographed for follow-up. Five patients underwent an AK biopsy for histopathology. Statistical analyses were performed using the Student t test. Results: At baseline, no statistically significant differences were observed regarding AK size between the two groups. After six months, among the cases, AKs had significantly decreased in size in 18/19 patients (88%). Among these 18 patients, seven patients (42%) had shown complete clinical regression and no patient developed new AKs. Conversely, among the controls, 91% showed an increase in AK size and/or developed new AKs. Seven pre-existing AKs progressed to squamous-cell carcinoma. Conclusion: Nicotinamide appears to be effective in preventing and treating AKs, although the mechanisms are still unclear. Further studies with a larger sample of organ transplant recipients and a longer follow-up period are needed to further support our conclusions.