Skin Cancer - Balancing the Message
Skin cancer is now the most common cancer in the UK, with approximately 100,000 new cases diagnosed every year. Balancing sun safety messages with emerging evidence of the health benefits of sun exposure needs a consistent approach to skin cancer advice says The British Association of Dermatologists.
Posted: 26 October 2009
Skin cancer is now the most common cancer in the UK, with approximately 100,000 new cases diagnosed every year. There are two main categories of skin cancer: melanoma and non-melanoma skin cancer (NMSC). Melanoma is less common than non-melanoma cancers, but is the most dangerous. Non-melanoma skin cancers are mainly comprised of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
Skin cancer is a largely preventable disease, with excess sun exposure being the primary cause. With so many charities and organizations working tirelessly to promote skin cancer prevention, it is inevitable that on occasions messages can become confused, or conflicting advice can arise.
The British Association of Dermatologists is therefore due to publish a paper which will provide a framework of recommendations on which skin cancer prevention messages should be based, and the supporting evidence for these recommendations. It is hoped that this will allow for a more unified, consistent approach to skin cancer prevention advice.
One of the issues addressed in this paper is the need to balance sun safety messages with emerging evidence of the health benefits of sun exposure.
Another more recent emphasis relates to people’s individual risk of skin cancer according to their skin type. It is no longer appropriate to provide blanket statements regarding sun protection without considering whether these are appropriate for naturally darker skinned people.
Vitamin D is produced in the skin in response to UVR, and solar radiation is the major source, providing about 90 percent, of vitamin D in humans. While we know that vitamin D deficiency carries negative health implications, some studies suggest that high levels of vitamin D may carry additional health benefits. A 2008 IARC report* concluded that for the time being, the definition of vitamin D deficiency should relate to the prevention of rickets, osteomalacia or muscular pain as opposed to internal malignancies. However, this is an emerging area of research which may support the role of vitamin D in disease prevention in future studies.
Messages relating to sun safety therefore need to incorporate methods of obtaining vitamin D and not advocate total sun avoidance.
It is difficult to establish a precise level of sun exposure that will provide each individual with vitamin D without significantly increasing their risk of skin cancer. This will vary according to the individual’s skin colour, geographical location / latitude, UV levels on a particular day, and more. Individuals’ personal vitamin D requirements will also differ.
Our current advice is to aim for 15 to 20 minutes of sun exposure a day, but to break this down into short bursts of 5 to 10 minutes when it is sunny, to minimize the risk of sunburn. It is not necessary to sunbathe; just exposing the face and forearms should be sufficient.
However, individuals at high risk of skin cancer should obtain as much vitamin D as possible from other sources, such as the diet and supplements. Those at high risk include people with very fair skin that easily burns, people with a personal or family history of skin cancer, people with lots of moles (more than 50) or patients being treated with immunosuppressive drugs.
While recognizing that not all individuals can be categorized into a specific skin type, dermatologists use a scale of I to VI to describe skin type with regard to the effects of UVR.
Type I: pale skin, burn very easily and rarely tan. They generally have light coloured or red hair and freckles.
Type II: usually burn but may gradually tan. They are likely to have light hair, and blue or brown eyes. Some may have dark hair but still have fair skin.
Type III: burn with long exposure to the sun but generally tan quite easily. They usually have a light olive skin with dark hair and brown or green eyes.
Type IV: burn with very lengthy exposures but always tan easily as well. They usually have brown eyes and dark hair.
Type V: have a naturally brown skin, with brown eyes and dark hair. They burn only with excessive exposure to the sun and their skin further darkens easily.
Type VI: have black skin with dark brown eyes and black hair. They burn only with extreme exposure to the sun and their skin further darkens very easily.
Skin types I and II are at the greatest risk of developing skin cancer. These skin types sunburn rapidly and therefore should avoid sun exposure during peak hours and should protect the skin with clothing. Skin types III and IV should protect themselves in strong sunshine, and during prolonged exposure. Types V and VI need only protect themselves during prolonged UVR exposure, such as if you work outdoors or are planning to spend long periods of time in the sun.
The British Association of Dermatologists’ Sun Awareness* campaign annually reviews research into skin cancer, including evidence pertaining to the sun safety / vitamin D debate, and tailors its messages accordingly. The current focus is on the importance of avoiding sunburn and heavy tanning, rather than avoiding the sun generally. The Sun Awareness campaign also promotes early detection.
For more information and to order free resources, visit www.bad.org.uk/sunawareness
* World Health Organization, International Agency for Research on Cancer. Vitamin D and Cancer. IARC Working Group Reports Volume 5, 2008.