Prevention of Skin Cancer in Organ-Transplant Recipients
Can oral nicotinamide help reduce the risk?
Background
Organ transplants are an important medical procedure that allows for a damaged organ to be replaced by a healthy one. One issue that arises with organ transplants is the potential for the new organ to be rejected from the body. This occurs because the patient’s immune system identifies the new organ as a foreign object and initiates an immune response. This immune response results in the rejection of the organ and makes the patient susceptible to infections.
In order to prevent this, doctors will usually prescribe immunosuppressive medications to allow the new organ to be integrated into the body. While this helps the organ transplant succeed, this leaves the patient immunocompromised, or more susceptible to diseases.
One illness that is particularly at a higher risk for organ-transplant patients is keratinocyte cancers. Keratinocytes are the primary cell found in the outermost layer of the skin and cancers of these cells are the most common type of skin cancer.
Patients are at a higher risk of developing keratinocyte cancers when they are exposed to UV radiation (which causes genetic damage and inhibits DNA repair) and when the immune response is weakened. Organ-transplant recipients are 50 times more likely to develop keratinocyte cancer than the general population.
Organ-transplant recipients are 50 times more likely to develop keratinocyte cancer than the general population.
The scientists in this study want to find a preventative method to help lower the risk of keratinocyte cancers in organ-transplant patients. Their hypothesis was to prescribe oral nicotinamide supplements. Nicotinamide is a form of vitamin B3 and plays a role in improving DNA repair and protecting cells from UV-radiation-induced damage. Previous studies have shown that oral nicotinamide supplements reduced the prevalence of keratinocyte cancers in healthy individuals so these scientists wanted to see if it could potentially help organ transplant patients.
Methods
158 adult organ-transplant recipients were selected for the study. Participants had to have had 2 diagnosed keratinocyte cancers within the last 5 years. The participants were split into two groups of 79 each. Group 1 took 500mg of nicotinamide twice a day for 12 months and group 2 took a placebo pill twice a day for 2 months. Participants had skin cancer checks performed by a dermatologist every 3 months for the 12-month duration of the study. The dermatologists checked for the appearance of new keratinocyte cancers.
Results
In the nicotinamide group, the average new keratinocyte cancers per patient was 2.6 +/- 3.2. In the placebo group, it was 2.7 +/- 3.7 cancers. This data had no statistical significance between the two groups and thus reveals that oral nicotinamide is not effective in preventing the development of keratinocyte cancers in organ-transplant recipients.
This result was surprising as nicotinamide had been effective in preventing the development of skin cancers in healthy patients. A previous study on oral nicotinamide in healthy individuals showed a 23% lower rate of non-melanoma cancer development (Chen). Additionally, the researchers did not find that different types of transplants or other characteristics such as age or sex affected the results.
This data had no statistical significance between the two groups and thus reveals that oral nicotinamide is not effective in preventing the development of keratinocyte cancers in organ-transplant recipients.
Negative results are fairly common in scientific studies but they are still important as we can learn from them and they can lead us closer to finding a successful treatment. Although this particular study was unsuccessful in finding a useful preventative supplement, it is still important to research ways to prevent keratinocyte cancers, especially for immunocompromised populations such as organ transplant recipients.
Additional Source
Chen, Andrew, et al. “A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.” The New England Journal of Medicine, vol. 373, 2015, pp. 1618–1626.
