Overview

• A JAMA Dermatology retrospective cohort of 33,822 veterans found a 14% overall reduction in subsequent skin cancers among those taking nicotinamide versus matched controls.
• Initiating 500 mg twice daily after a first skin cancer was associated with about a 54% lower risk of another cancer, with benefit declining when started after additional cancers.
• Reductions were reported for basal cell carcinoma and cutaneous squamous cell carcinoma, with the largest effect seen in cSCC.
• Among solid organ transplant recipients, no overall risk reduction was observed, though earlier use was linked to fewer cSCCs in selected subgroups.
• Authors emphasize the study shows association rather than causation and call for prospective trials, noting the older, predominantly male VA cohort and advising use as an adjunct to standard sun protection.