Vitamins B to reduce skin Cancer

Introduction

The most common malignancy in the United States is nonmelanoma skin cancer with an estimated 5.4 million new cases in 2012.1 And the incidence is rising. In 2006 there were an estimated 4 million cases.1 Topical sunscreens are effective prevention for nonmelanoma skin cancer when they are used as directed but compliance with these is poor, even in patients who have already been diagnosed with melanoma.2 Long used for various dermatologic conditions, niacinamide is now being looked at for its effects on adenosine triphosphate (ATP) production and skin immunity.3 This article will review niacinamide and its role in the prevention of nonmelanoma skin cancers.

Mechanism

The leading cause of skin cancer is UV light from the sun.2,4 UV light inhibits the production of ATP, a key component in cellular energy, creating an “energy crisis.”3 This decrease in cellular energy reduces the skin’s immunity and the ability to repair DNA, which can both lead to skin cancer.3,5

Niacinamide, also known as nicotinamide, is the amide form of vitamin B3. It enhances ATP production, boosting cellular energy which protects against skin immunosuppression and leads to DNA repair.3,5,6

A randomized, double-blind, crossover trial compared the immunosuppressive effects of UV radiation on 64 patients receiving oral nicotinamide 500 mg or 1500 mg daily versus placebo.7 The Mantoux model of skin immunity was used and results showed significant reduction in UV immunosuppression in the nicotinamide treated group.7

Efficacy

The recent Oral Nicotinamide to Reduce Actinic Cancer (ONTRAC) study was a phase three, randomized, double-blind, placebo-controlled study that compared nicotinamide 500 mg orally twice daily to placebo in 386 Australian patients for 12 months.6 Participants were immune competent and had at least two confirmed nonmelanoma skin cancers in the five years prior to enrollment in the study. The primary endpoint was number of new nonmelanoma skin cancers in 12 months with secondary endpoints of the number of basal cell carcinomas, squamous cell carcinomas, and actinic keratoses. The mean age of patients was 66 years, the mean number of previous skin cancers was eight, and 63% of those enrolled were men. The number of new nonmelanoma skin cancers was significantly lower in the nicotinamide group at an average of 1.77 compared to 2.42 in the placebo group (RRR 0.23 [95% CI; 0.04-0.38; p=0.02]). The ONTRAC study is not yet published.

Actinic keratoses are premalignant lesions that can progress to nonmelanoma skin cancer.2 Researchers are also evaluating niacinamide for use in patients with actinic keratoses. Preliminary evidence suggests that use of oral niacinamide (500 mg once or twice daily) may help to reduce actinic keratoses lesions in these patients.8

Safety

There was no difference in adverse drug events reported with nicotinamide 500 mg twice daily compared to placebo in the ONTRAC study mentioned above.6

A full literature review in 2000 concluded that niacinamide was very well tolerated at doses up to 3 g per day.9 Adverse effects reported with oral doses of greater than 6 g per day include nausea, vomiting, headache, fatigue, and dizziness.7

There have been no well-established drug interactions reported with usual doses of niacinamide.