- Sunlight is a risk factor for non-melanoma skin cancer, with lifetime UVB exposure important for squamous cell carcinoma and sunburning for basal cell carcinoma.
- Higher vitamin D levels may increase the risk of squamous cell carcinoma.
Non-melanoma skin cancer (NMSC) occurs when malignant (cancer) cells form in the tissues of the skin.
The most common type of NMSC is basal cell carcinoma (BCC), accounting for 80% of skin cancer in the U.S.. Squamous cell carcinoma (SCC) occurs much less frequently, accounting for 16% (Melanoma accounts for the remaining 4%).
Basal cells are found in the lower layer of the skin, while squamous cells are found on the surface of the skin.
It was estimated that 2 million people in the United States were treated for non-melanoma skin cancer in 2006. However, only 3000 people die from non-melanoma skin cancer annually, with most of these deaths due to squamous cell carcinoma.
Important risk factors for non-melanoma skin cancer include:
- Lighter skin
- Red hair
- Lifetime ultraviolet-B (UVB) exposure
Vitamin D and non-melanoma skin cancer
Vitamin D levels
There is some evidence that those with higher vitamin D levels have a higher rate of basal cell carcinoma. However, UVB is a risk factor for basal cell carcinoma independent of vitamin D. As such, in the absence of UVB light, it is not clear that vitamin D is a risk factor for basal cell carcinoma. There is also laboratory evidence that vitamin D reduces the risk of basal cell carcinoma.
For both basal and squamous cell carcinoma, there is evidence that some of the vitamin D receptor (VDR) varieties are associated with increased risk. Since the active form of vitamin D, calcitriol, activates vitamin D receptors, which then turn genes on and off, this finding suggests role of vitamin D in reducing risk of these cancers.
Higher vitamin D levels might reduce the risk of non-melanoma skin cancer. However, more research is required.
There is no evidence that vitamin D is beneficial in treating non-melanoma skin cancer. However, since higher vitamin D levels have been found associated with increased survival rates for several other types of cancer, vitamin D might help. However, since skin cancer is easy to treat with conventional methods, they should be the first approach.
Vitamin D levels in Australia, the United Kingdom, and the United States have been dropping. Most likely this is due to sun exposure warnings from dermatologists, leading to sun avoidance and increased use of sunscreens. This is unfortunate because the health benefits of vitamin D produced by solar UVB greatly outweigh the risks of skin cancer in terms of costs, rates of many health conditions, and lives lost.
Current thought is that since UVB from sunlight is the most important source of vitamin D for most people, people might try to spend a few minutes in the sun with as much body surface area exposed when the sun is high enough in the sky that vitamin D can be produced. The way to tell if the sun is high enough is if one’s shadow is shorter than one’s height, it is. One should not spend so much time in the sun that any reddening or burning occurs.
Find out more…
We will be adding a detailed evidence summary on this topic in the near future. Please check back soon to find out more.
Page last edited: 05 August 2011