Risk factors for melanoma and non-melanoma skin cancers

Skin types, sun safety and evidence for preventative

strategies

Skin Types

• Fitzpatrick skin types chart- classification system for skin typing

• based on a person's complexion and responses to sun exposure

• Important indicator of Skin cancer risk

• Also used to determine suitability for certain cosmetic procedures etc.

• Determined using a survey

Fitzpatrick Skin Type i- vi • TYPE 1: Highly sensitive, always burns, never tans. Example: Red

hair with freckles• TYPE 2: Very sun sensitive, burns easily, tans minimally. Example:

Fair skinned, fair haired Caucasians• TYPE 3: Sun sensitive skin, sometimes burns, slowly tans to light

brown. Example: Darker Caucasians.• TYPE 4: Minimally sun sensitive, burns minimally, always tans to

moderate brown. Example: Mediterranian type Caucasians.• TYPE 5: Sun insensitive skin, rarely burns, tans well. Example:

Some Hispanics, some Blacks• TYPE 6: Sun insensitive, never burns, deeply pigmented. Example:

Darker Blacks.

http://www.skincancer.org/fitzpatrick-skin-quiz.html

Risk Factors- MelanomaSun exposure and UV radiation  

Although a direct causal relationship between solar ultraviolet (UV) radiation and melanoma cannot be demonstrated experimentally, the evidence from indirect studies is overwhelming and leaves little doubt that UV exposure is a major risk factor – higher rates of melanoma in people with extensive or repeated intense

exposure to sunlight– The majority of melanomas develop on sun-exposed skin, particularly in

areas that are more susceptible to sunburn– Individuals with naturally dark skin or whose skin darkens easily upon sun

exposure have lower rates of melanoma, supporting the concept that greater penetration of UV light into the skin results in a higher risk

– Adjusted for skin type, the geographic incidence of melanoma is highest in equatorial areas and decreases proportionately with distance from the

equator, with its correspondingly lower level of UV exposure

http://clinicalevidence.bmj.com.ezproxy.library.uq.edu.au/ceweb/conditions/skd/skd.jsphttp://www.uptodate.com.ezproxy.library.uq.edu.au/

Timing and Type of UV exposure

• Ultraviolet B radiation (UV-B) appears more closely associated with the development of melanoma than UV-A. However a causal link to UV-A exposure is also supported by data from patients using tanning beds

• Intermittent exposure and sunburn, particularly in adolescence or childhood are strongly associated with an increased risk of melanoma, while occupational exposure do not confer an increased risk. These findings support the hypothesis that melanoma risk is affected primarily by intermittent intense sun exposure

http://clinicalevidence.bmj.com.ezproxy.library.uq.edu.au/ceweb/conditions/skd/skd.jsphttp://www.uptodate.com.ezproxy.library.uq.edu.au/

Other Risk Factors for Melanoma• Skin type and hair colour, the number of naevi • Occupation…. But only in the sense of increased sun exposure… • Diets rich in vitamin D and carotenoids and low in alcohol may be

associated with a reduced risk for melanoma • Smoking • Family History – Genetics BAF, P16

-Familial atypical multiple mole and melanoma (FAMMM) syndrome • Atypical mole syndrome (AMS), also called dysplastic nevus

syndrome (DNS)• Personal History of melanoma or nonmelanoma skin cancer• Immunosuppression

http://clinicalevidence.bmj.com.ezproxy.library.uq.edu.au/ceweb/conditions/skd/skd.jsphttp://www.uptodate.com.ezproxy.library.uq.edu.au/

Risk Factors of non-melanoma skins cancer

• Essentially the same as for melanoma• radiotherapy, phototherapy, male gender• number of blistering sunburns• Clinical signs of chronic skin damage, especially solar

keratoses• Most important difference

– Nonmelanoma cancers are associated with cumulative sun exposure and occur most frequently in areas maximally exposed to the sun (eg, face, dorsal hands, forearms). ie. Occupation more significant RF

– melanomas tend to be associated with intense, intermittent sun exposure and sunburns and they frequently occur in areas exposed to the sun only sporadically

http://clinicalevidence.bmj.com.ezproxy.library.uq.edu.au/ceweb/conditions/skd/skd.jsphttp://www.uptodate.com.ezproxy.library.uq.edu.au/

Sun Safety- Slip, Slop, Slap Slip on sun protective clothing 

Choose clothing that:Covers as much skin as possible e.g. long sleeves and high necks/collars.Is made from close weave materials such as cotton, polyester/cotton and linen.Is dark in colour to absorb UV rays. White and lighter colours reflect UV onto skin.If used for swimming, is made from materials such as lycra, which stays sun protective when wet.

Slop on SPF 30+ sunscreen Make sure your sunscreen is broad spectrum and water resistant. Sunscreen should not be used to increase the amount of time you spend in the sun and should always be used with other forms of protection. Apply sunscreen liberally to clean, dry skin at least 20 minutes before going

outside and reapply every two hours. 

Slap on a hat A broad brimmed, legionnaire or bucket style hat provides good protection for the face, nose, neck and ears, which are common sites for skin cancers. Caps and visors do not provide adequate protection. Choose a

hat made with closely woven fabric – if you can see through it, UV radiation will get through. Hats may not protect you from reflected UV radiation, so also wear sunglasses and sunscreen to increase your level of protection. 

Seek shade Make use of trees or built shade structures, or bring your own! Staying in the shade is an effective way to reduce sun exposure. Whatever you use for shade, make sure it casts a dark shadow and use other protection (such as clothing, hats, sunglasses and sunscreen) to avoid reflected UV radiation from nearby surfaces. 

Slide on some sunglasses Sunglasses and a broad brimmed hat worn together can reduce UV radiation exposure to the eyes by up to 98 per cent. Choose close-fitting wrap-around sunglasses that meet the Australian Standard AS 1067. Sunglasses are as important for children as they are for adults. 

Other SunSmart Tips

• Take extra care between 10am and 3pm when UV radiation is most intense. 

• Look out for the SunSmart UV Alert which tells you the time period in which you need to be SunSmart – it appears on the weather page of most daily newspapers

• Check you skin regularly and see a doctor if you notice any unusual skin changes.  If you have a lesion that doesn’t heal, or a mole that has suddenly appeared, changed in size, thickness, shape, colour or has started to bleed, ask your doctor for a skin examination

http://www.cancerqld.org.au/page/prevention/skin_cancer/

Evidence for preventative strategies - do they prevent cancer?

• The International Agency for Research on Cancer has issued a consensus statement saying that, “although sunscreens reduce the likelihood of sunburn, and are therefore likely to reduce squamous cell carcinoma, the evidence regarding the effect of sunscreens on basal cell carcinoma or melanoma is inconclusive. This organisation warns that use of sunscreens to extend the period of intentional sun exposure may increase the risk of melanoma.” statement also suggested that “sunscreens of sun protection factor 15 or greater and a star rating for ultraviolet A light protection of 3–4 may have a role if used appropriately to reduce ultraviolet exposure, rather than being used to prolong the time spent in direct sunlight.”

• data concerning modern sunscreens that have higher sun protection factor values and increased ultraviolet A blocking will not be available for several years

• Conclusion: Sun avoidance is best.

• http://clinicalevidence.bmj.com.ezproxy.library.uq.edu.au/ceweb/conditions/skd/1705/1705_I1.jsp

Issues with Sunscreen Studies

• Unethical to conduct RCT

• individuals apply significantly less than the 2 mg/cm2 (approximately 30 to 35 mL/ body application) of sunscreen, used to determine the SPF

• People who wear sunscreen are often those who do spend more time outside, so some studies find sunscreen use increased melanoma risk…..

Questions1. What is your skin type??

Part I: Genetic Disposition

Your eye color is:Light blue, light gray or light green = 0Blue, gray or green = 1Hazel or light brown = 2  Dark brown = 3Brownish black = 4 

Your natural hair color is:Red or light blonde = 0Blonde = 1Dark blonde or light brown = 2Dark brown = 3

Black = 4

Your natural skin color (before sun exposure) is:Ivory white = 0Fair or pale = 1Fair to beige, with golden undertone = 2Olive or light brown = 3 Dark brown or black = 4

How many freckles do you have on unexposed areas of your skin?Many = 0Several = 1A few = 2Very few = 3None = 4

Total score for genetic disposition: _______

Part II: Reaction to Extended Sun Exposure How does your skin respond to the sun?

Always burns, blisters and peels = 0Often burns, blisters and peels = 1Burns moderately = 2Burns rarely, if at all = 3Never burns = 4

 Does your skin tan?

Never -- I always burn = 0Seldom = 1Sometimes = 2Often = 3Always = 4

How deeply do you tan?Not at all or very little = 0Lightly = 1Moderately = 2Deeply = 3My skin is naturally dark = 4

 How sensitive is your face to the sun?

Very sensitive = 0Sensitive = 1Normal = 2Resistant = 3Very resistant/Never had a problem = 4

Total score for reaction to sun exposure: _______

Add up your genetic disposition and sun exposure totals to find your Fitzpatrick Skin Type: 

http://www.skincancer.org/fitzpatrick-skin-quiz.html

0-7 I

8-16 II

17-25 III

25-30 IV

over 30 V -VI

Question 2.

Who has a greater risk of melanoma?

a) a office worker who gets a blistering sunburn every christmas

b) a builder who maintains a deep tan year round