Vitamin B Derivative Reduces Risk for Further Skin Cancer

Zosia Chustecka

An inexpensive vitamin B₃ product, widely available over the counter, has been shown to reduce significantly the risk of developing further skin cancers in patients who have already been diagnosed with nonmelanoma skin cancer. The product is nicotinamide, taken orally 500 mg twice daily.

"This is the first clear evidence that we can reduce skin cancers using a simple vitamin, together with sensible skin protection," commented senior study author Diona Damian, MBBS, PhD, professor of dermatology at the Dermatology University of Sydney in Australia.

"It is safe and...inexpensive, and this one is ready to go into the clinic," she said.

Nonmelanoma skin cancer is the most common cancer worldwide, she said.

In Australia, it is four times more common than any other cancer, and it affects more than half the population during their lifetime.

The finding, from the Australian ONTRAC (Oral Nicotinamide to Reduce Actinic Cancer) study, was presented during a press briefing held in advance of the American Society of Clinical Oncology (ASCO) 2015 Annual Meeting.

The results released today show that patients who took nicotinamide 500 mg twice daily for 1 year showed a 23% reduction in new diagnoses of nonmelanoma skin cancer, compared with those who took placebo (P = .02). Specifically, new diagnoses of basal cell carcinoma were reduced by 20%, squamous cell carcinoma by 30%, and actinic keratoses by 13%.

During the year-long study, the patients in the placebo group developed a median of 2.5 new skin cancers, whereas those in the nicotinamide group had a median of 1.77 new cancers.

We have a remarkably simple and inexpensive way to help people avoid repeat diagnosis of some of the most common skin cancers.

"With this study, we have a remarkably simple and inexpensive way to help people avoid repeat diagnosis of some of the most common skin cancers," commented ASCO President Peter Yu, MD, who is director of cancer research at the Palo Alto Medical Foundation in Mountain View and Sunnyvale, California. During the press briefing, he described this research as a "major advance" in prevention.

In the United States, about 5 million people each year are diagnosed with nonmelanoma skin cancer.

High-Risk Skin Cancer Patients

The study was conducted at two tertiary treatment centers in Sydney from 2011 to 2014. It involved 386 patients who had at least two nonmelanoma skin cancers in the last 5 years (median was eight skin cancers, but one patient had 52 lesions), and hence were considered to be at high risk. The study population reflects the sort of patients typically seen in a skin cancer clinic, the researchers note; the average age was 66 years (range, 30 to 90), and two-thirds of the patients were men. Many patients also had ongoing concomitant disease, such as heart disease, arthritis, hypertension, and chronic lung disease.

Patients were randomly allocated to receive either the vitamin or placebo, and underwent regular dermatologist review every 3 months. Discontinuation rates were similar for the two groups, and there were no clinically relevant differences in adverse events rates between the two groups, the researchers report. "Nicotinamide was very well tolerated," Dr Damian said, and there were no interactions with other medications that the patients were taking.

The benefit from nicotinamide started to be seen at 3 months, but the benefit wore off quickly when patient stopped taking the vitamin, Dr Damian noted. In the 6 months after the year-long trial, when patients had stopped treatment but were still being monitored, the rate of new skin cancers was similar in the two groups, she said. "You have to keep taking the tablet in order for it to be effective," she added.

Nicotinamide "presents a new chemopreventive opportunity against nonmelanoma skin cancer that is readily translatable into clinical practice," the researchers conclude.

They speculate that nicotinamide offered protection against the development of subsequent skin cancer by working in two ways: enhancing the repair of DNA in skin cells damaged by sunlight, and preventing immune suppression in the skin by ultraviolet light.

Approached for comment, John Lear, MD, from Manchester University and from the Dermatology Department at Salford Royal Hospital in the United Kingdom, agreed that this is "very exciting and promising research to prevent skin cancer using a simple therapy which could easily be translated into clinical practice quickly with a large clinically meaningful reduction in skin cancers and actinic keratoses."

However, Dr Lear pointed out that the study was conducted in a relatively small number of patients, and the Australian high-risk population may not be representative of skin cancer populations elsewhere, particularly in less sunny climates. In addition, he told Medscape Medical News that "it is surprising to see such a reduction in basal cell carcinoma numbers given such a short period of treatment, given that they often develop many years after the ultraviolet exposure that caused them."

Not for General Population

During the press briefing, Dr Damian emphasized that this research shows the benefits of nicotinamide in patients who already have skin cancer. When asked about the general population, who may be worried about sun-damaged skin, she emphasized that the data are not there. It may be that nicotinamide would also reduce their risk of developing skin cancer, "but we don't know that," added press moderator Gregory Masters, MD.

Dr Damian also emphasized the importance of sun protection measures.

The study received funding from Australia's National Health and Medical Research Council. Dr Damian has disclosed no relevant financial relationships. Two study coauthors report consulting agreements with several pharmaceutical companies. Dr Yu reports stock and other ownership interests with ContraFect, Citrix Systems, EMC Corp., Google, IBM, Oracle, FireEye, and Apple; and receiving research funding from Berg Pharmaceuticals.

American Society of Clinical Oncology (ASCO) 2015 Annual Meeting: Abstract 9000. To be presented May 30, 2015.