Three Cheers for B₃?

At the recent American Society of Clinical Oncology Annual Meeting, Martin et al presented data from the Australian Oral Nicotinamide to Reduce Actinic Cancer (ONTRAC) study. This prospective double-blind, randomized, controlled trial examined 386 immunocompetent patients with 2 or more nonmelanoma skin cancers (NMSCs) in the last 5 years (average, 8). The patients were randomized to receive oral nicotinamide 500 mg twice daily or placebo for 1 year, resulting in significant reduction of new NMSCs (average rate 1.77 vs 2.42; relative rate reduction, 23%; P=.02), with similar results for basal and squamous cell carcinomas. Actinic keratosis counts were reduced throughout the year by up to 20%, peaking at 9 months. No differences in adverse events were noted between the treatment and placebo groups.

What’s the issue?

High-risk NMSC patients present a challenge to dermatologists, as their need for constant surveillance, field therapy for actinic keratoses, and revolving visits between skin examinations and procedural modalities such as Mohs micrographic surgery can be staggering. Chemopreventive strategies pose difficulties, especially for elderly patients, due to tolerability and adherence, skin irritation and cosmetic limitations of topical therapies such as 5-fluorouracil, and inadequacy or financial inaccessibility of oral therapies such as acitretin.

Nicotinamide is a confusing supplement, as it is also called niacinamide. One of the 2 forms of vitamin B₃, nicotinic acid (or niacin) is the other form and can be converted to nicotinamide in the body. It has cholesterol and vasodilatory/flushing effects that nicotinamide itself does not. Therefore, these supplement subtypes are not generally interchangeable.

Nicotinamide is postulated to enhance DNA repair and reverse UV immunosuppression in NMSC patients and is a well-tolerated and inexpensive supplement (approximately $10 a month for the dosage in this study). Although the decrease in skin cancer number per year seems modest in this study, my patients would likely welcome at least 1 fewer surgery per year and much less cryotherapy or 5-fluorouracil cream, especially if it is as simple as buying the supplement at the grocery store as they do for their fish oil capsules and probiotics. Does vitamin B₃ hold promise for your high-risk NMSC patients?

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