SUMMARY: Skin cancer is the most common of all cancers. Approximately, 3.5 million cases of Basal cell and Squamous cell skin cancer (Non-Melanomatous) are diagnosed in the US each year. Most Non-Melanomatous skin cancers develop on the sun-exposed areas of the skin and Basal cell cancers tend to be slow growing and rarely metastasize, whereas Squamous cell cancers are more likely to grow into deeper layers of skin and metastasize. There has been a 35% increase in the incidence of Non-Melanomatous skin cancers between 2006 and 2012 and there has been a 17% increase in the incidence of Basal cell carcinomas over the past 15 years. Patients with Non-Melanomatous skin cancer are at an increased risk of developing a new primary, including breast and lung cancer in woman and prostate cancer in men. A major risk factor for most skin cancers is exposure to UltraViolet (UV) radiation, which damages the DNA of skin cells and suppresses cutaneous immunity. The main source of UV rays are sunlight, tanning lamps and tanning beds. The 3 main types of UV rays include UVA rays, UVB rays that mainly cause sunburns and UVC rays that do not penetrate through our atmosphere and are not in sunlight. Most indoor tanning beds give off large amounts of UVA rays, which have been found to increase skin cancer risk. It appears that there are no safe UV rays. Nicotinamide is an amide form of Vitamin B3 and unlike Nicotinic acid does not cause vasodilatation and associated side effects. Severe Nicotinamide deficiency causes Pellagra, which is characterized by photosensitive dermatitis, dementia, diarrhea and death. Nicotinamide enhances DNA repair after UV exposure and reduces UV radiation induced immunosuppression and in previously published studies was shown to decrease the formation of Actinic keratoses.
The ONTRAC (Oral Nicotinamide to Reduce Actinic Cancer) trial is a double-blind, phase III Study, in which 386 patients were randomly assigned to receive either Nicotinamide 500 mg PO twice daily (N=193 patients) or placebo (N=193 patients), for a period of 12 months. Enrolled patients had 2 or more histologically confirmed Non-Melanomatous skin cancers during the previous 5 years. The mean age was 66 years and 63% of the enrollees were men. Skin evaluations were performed by Dermatologists every 3 months. The primary endpoint was the number of new Non-Melanomatous skin cancers at 12 months and secondary endpoints included number of Squamous cell carcinomas, Basal cell carcinomas, and Actinic keratoses over the same study period. Over the 12 month study period, it was noted that patients in the placebo group developed an average of 2.4 new Non-Melanomatous skin cancers compared with 1.8 in the Nicotinamide group. This meant a Relative Risk Reduction (RRR) of 0.23 (P= 0.02). With regards to the specific subtypes, there was an average of 1.7 new cases of Basal cell carcinoma for patients who received placebo compared to 1.3 new cases for patients who received Nicotinamide. The Relative Risk Reduction was 0.20 (P=0.1). For Squamous cell carcinomas, there was an average of 0.7 cases for patients in the placebo group compared with 0.5 in the Nicotinamide group. The Relative Risk Reduction was 0.30 (P= 0.05). With regards to Actinic keratosis, there was a Relative Risk Reduction of 11% at 3 months (P=0.01), 14% at 6 months (P<0.001), 20% at 9 months (P<0.0001) and 13% at 12 months (P<0.005).
Based on this data the authors concluded that Nicotinamide, an inexpensive, over-the-counter Vitamin supplement, significantly reduces the incidence of Non-Melanomatous skin cancers by 20-30%, in high risk patients and may be an effective chemopreventive agent for Non-Melanomatous skin cancers. Oral nicotinamide to reduce actinic cancer: A phase 3 double-blind randomized controlled trial. Martin AJ, Chen A, Choy B, et al. J Clin Oncol 33, 2015 (suppl; abstr 9000)