ASCO 2015: Oral Vitamin Reduces Risk of Common Nonmelanoma Skin Cancers in High-Risk Patients
The Australian ONTRAC trial showed that a form of vitamin B3 called nicotinamide significantly reduced the rates of new skin cancers in people at high risk of the disease. Taken as a twice-daily pill, nicotinamide reduced the incidence of new nonmelanoma skin cancers by 23%. These findings were presented today at a presscast in advance of the 2015 ASCO Annual Meeting (Abstract 9000).
Nicotinamide is safe, affordable, and available over the counter in most countries. The findings have the potential to decrease the health burden and economic cost of skin cancer, the most common form of cancer in fair-skinned populations worldwide.
“This is the first clear evidence that we can reduce skin cancers using a simple vitamin, together with sensible sun protection. We hope that these findings can be immediately translated into clinical practice,” said senior study author Diona Damian, MBBS, PhD, Professor of Dermatology at the University of Sydney. “However, people at high risk of skin cancer will still need regular checkups with their doctor.”
Study Background
The primary cause of nonmelanoma skin cancer is sun exposure. Despite intensive sun protection campaigns, the incidence of skin cancer is continuing to increase worldwide. In the United States, about 5 million people are treated for nonmelanoma skin cancer each year, and in Australia, nonmelanoma skin cancers affect more than half of the population during their lifetime.
In this study, 386 patients who had at least two nonmelanoma skin cancers in the past 5 years (therefore considered to be at high risk) were randomly assigned to receive daily nicotinamide or placebo for 12 months. The study population reflected the mix of patients typically seen in a skin cancer clinic—the average age was 66 years, and two-thirds of the patients were men. Many of the patients had ongoing medical issues such as heart disease, arthritis, hypertension, and chronic lung disease.
Study Findings
The rates of new nonmelanoma skin cancer diagnoses were 23% lower in the nicotinamide group compared with the placebo group. The number of actinic keratosis was reduced in the nicotinamide group by 11% at 3 months and by 20% at 9 months of usage. Although nicotinic acid, which is a different form of vitamin B3, is known to cause side effects including headaches, flushing, and hypotension, nicotinamide lacks these side effects and was not associated with any serious side effects in the study.
The most common types of nonmelanoma skin cancer are basal cell and squamous cell carcinomas. Squamous cell carcinomas can spread to lymph nodes and internal organs. Basal cell carcinomas rarely spread but can cause cosmetic problems, as they occur often on the face. Nicotinamide had comparable efficacy in preventing both cancers.
Mechanism of Action
Ultraviolet (UV) radiation in sunlight causes skin cancer via two key pathways: DNA damage and suppression of skin immunity. This study builds on a decade of preclinical and early clinical studies, which suggested that nicotinamide both enhances the repair of DNA in skin cells damaged by sunlight and protects the skin’s immune system against UV light.
DNA repair is an energy-intensive process. UV radiation actively blocks energy production in skin cells. Cells convert nicotinamide into a molecule called nicotinamide adenine dinucleotide, which is essential for cellular energy production. The researchers believe that nicotinamide thus helps replenish cellular energy after sunlight exposure, giving cells the energy boost they need to repair DNA damage and prevent immune suppression.
Further studies are planned to determine whether nicotinamide can help reduce skin cancers in people with suppressed immune systems, such as organ-transplant recipients who have to take lifelong immunosuppressive medications. People with suppressed immune systems have skin cancer rates up to 50 times higher than those with normal immune systems.
This study was supported by Australia’s National Health and Medical Research Council (NHMRC).
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
