Nicotinamide Prevents Actinic Keratoses, Basal Cell Carcinomas, and Squamous Cell Carcinomas

Chen et al (N Engl J Med. 2015;373:1618-1626) performed a multicenter, phase 3, double-blind, randomized, placebo-controlled trial. Results demonstrated that nicotinamide effectively decreased the rates of new nonmelanoma skin cancers (NMSCs) and actinic keratoses (AKs) in high-risk patients who had at least 2 histologically confirmed NMSCs in the last 5 years. In comparison to participants who received placebo, individuals who received nicotinamide 500 mg twice daily during the 12-month study (branded with a predictive acronym ONTRAC [oral nicotinamide to reduce actinic cancer]) had reduced rates of AKs of up to 20%, basal cell carcinomas of 20%, squamous cell carcinomas of 30%, and NMSCs of 23%. However, the effect of nicotinamide on NMSCs was not maintained at evaluation 6 months after discontinuation; the number of basal cell carcinomas was similar, and the number of squamous cell carcinomas was greater in participants who received nicotinamide in comparison to individuals who received placebo.

What’s the issue?

The risk for skin cancer is increased by UV radiation that damages DNA, suppresses cutaneous immunity, and inhibits DNA repair by depleting cellular adenosine triphosphate. Nicotinamide, an amide form of vitamin B₃, has been demonstrated to not only reduce UV radiation–induced immunosuppression but also to prevent UV radiation–induced adenosine triphosphate depletion and glycolic blockade. Nicotinamide, which is classified as a food additive, also has neuroprotective and antioxidant functions and reduces pigmentation, wrinkles, and sebum production. Although oral nicotinamide has been demonstrated to reduce NMSCs and AKs, topical application has been shown to improve many skin conditions such as acne, atopic dermatitis, isoniazid-induced pellagra, and rosacea.

In contrast to nicotinic acid (niacin), nicotinamide is not associated with headaches, hypotension, flushing, itching, or vasodilatation. At high oral doses, side effects of nicotinamide that have been hypothesized or observed in animals, humans, or both have included the development of Parkinson disease, insulin sensitivity and diabetes mellitus, and liver toxicity. Although there are no reports in humans of growth retardation, teratogenicity, or oncogenicity, Rolfe (J Cosmet Dermatol. 2014;13:324-328) discussed that fetal blood levels of nicotinamide are greater than corresponding maternal blood levels because it is able to cross the placenta. However, according to Chen et al, no clinically significant between-group differences were found with respect to the number or types of adverse events that occurred in the placebo participants and the individuals who received 1000 mg daily of nicotinamide. Chen et al implied that there were additional benefits in the recipients of nicotinamide with regards to cognitive function and transepidermal water loss.

Perhaps all patients with a history of AKs, basal cell carcinomas, or squamous cell carcinomas should receive lifelong nicotinamide. Also, it might be reasonable to consider that all individuals older than 18 years who are not pregnant or breastfeeding with increased sun exposure but no history of AKs or NMSC add nicotinamide to their daily diets as a proactive measure for chemoprevention. Would you suggest nicotinamide to your patients?

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