Louis Roller takes an in-depth look at skin cancer
Approximately two in three Australians will be diagnosed with skin cancer by the time they are 70, with more than 750,000 people treated for one or more non-melanoma skin cancers in Australia each year.
Non-melanoma skin cancer is more common in men, with almost double the incidence compared to women.
Melanoma is the third most common cancer in Australians. In 2014, 13,134 Australians were diagnosed with melanoma and these are a major cause of mortality from cancer, particularly in young adults.
Every year, in Australia:
- skin cancers account for around 80% of all newly diagnosed cancers;
- the majority of skin cancers are caused by exposure to the sun;
- GPs have over 1 million patient consultations per year for skin cancer;
- the incidence of skin cancer is one of the highest in the world; and
- In 2015, 2162 people died from skin cancer in Australia, 1520 from melanoma and 642 from non-melanoma skin cancers.
UV rays are the part of sunlight that damages skin. A sun tan is a sign of skin damage from UV rays and does not protect against skin cancer. UV radiation can also damage eyes.
A suntan is actually a response to injury. Of the three types of solar radiation (visable, UV, IR), only the ultra-violet (UV) spectrum produces sunburn and suntan.
The UV spectrum ranges from 200-400 nanometres (nm). Natural and artificial UV light can be further subdivided into three bands: UV-A, UV-B and UV-C of which, UV-B is the most dangerous.
UV-B (wavelength 290-320 nm) causes the usual sunburn reaction and stimulates tanning. It has long been associated with sunlight skin damage, including the various skin cancers. It is the most erythrogenic and melanogenic of the three UV radiation bands.
Small amounts of this UV-B radiation are required for normal vitamin D synthesis in the skin.
Three-step sequence after mild to moderate sunlight UV radiation exposure:
- Erythema occurs within 20-30 minutes as a result of oxidation of bleached melanin and dilatation of dermal venules.
- The initial erythema fades rapidly and true sunburn erythema begins 2 to 8 hours after initial exposure to the sun.
- Dilatation of the arterioles results in increased vascular permeability, localised oedema and pain, which reaches its peak after 14 to 20 hours and can last for 24 to 72 hours.
More UV rays reach the earth’s surface in the middle of the day, during summer, at higher elevations (altitudes) and closer to the equator. Less UV radiation reaches the earth’s surface in the morning and evening.
- UV radiation is strongest and most dangerous from 10 am to 2 pm (11am to 3pm daylight saving time).
- clouds do not block out damaging UV radiation.
- UV radiation is not related to temperature, so sunburn can still occur on a cool day.
- light-coloured and shiny surfaces (e.g. concrete, sand, snow, water) reflect sunlight and increase exposure to UV radiation.
- sunlight passes through water and can damage skin while swimming.
- solariums and sunbeds produce UV radiation up to three times as strong as the midday summer sun.
Those at risk of skin cancer are those who have:
- a lot of exposure to UV radiation over their lifetime
- been sunburnt
- a large number of moles or unusual moles
- fair skin that burns easily, has freckles and does not tan
- a family history of skin cancer
- used solariums, sunlamps or sunbeds.
The three major types of skin cancer are:
- is the most dangerous skin cancer
- may be a new spot, or a spot, freckle or mole that changes colour, size or shape
- usually has an irregular or smudgy outline and may have more than one colour
- grows over weeks to months and can appear anywhere on the body
- can be surgically removed in most people if treated early
- can spread to other parts of the body if not treated.
- Squamous cell carcinoma (SCC)
- looks like a thickened, red, scaly spot that may bleed or form an ulcer
- usually appears on parts of skin that get the most sun (e.g. nose, cheeks, forehead, arms and back of hands)
- grows quickly over weeks or months
- can usually be successfully treated if found early.
- Basal cell carcinoma (BCC)
- is the most common but least dangerous skin cancer
- is red, pale or pearly in colour
- looks like a round or flattened lump or scaly area
- may become an ulcer or sore that doesn’t heal
- usually appears on skin that gets the most sun
- grows slowly
- can usually be successfully treated if found early.
Other skin spots
Sunspots, freckles and moles may be warning signs of sun damage and future skin cancer.
Solar keratosis (sunspots)
- are red, flat, scaling, dry patches
- may sting if scratched
- appear on skin that gets the most sun
- are most common in people over 40 years of age.
Freckles and moles
- are harmless brown and black spots on the skin
- are usually round or oval-shaped, and may be raised
- may increase in number with sun exposure.
The sooner a skin cancer is identified and treated, the better the chances of avoiding surgery or, in the case of a serious melanoma or other skin cancer, potential disfigurement or even death.
Pharmacists should encourage their clients to look for:
- any crusty, non-healing sores
- small lumps that are red, pale or pearly in colour
- new spots, freckles or any moles changing in colour, thickness or shape over a period of weeks to months.
Further, pharmacists should encourage people to look for the UV Alert each day in the newspaper weather forecast or on the Australian Bureau of Meteorology website, or get the free SunSmart app for smartphone. When the UV Index is 3 or above, sun protection is required.
Remember! Prevention is better than cure: Slip, Slop, Slap.
Therapeutic Guidelines: Dermatology, Version 4, 2015
Associate Professor Louis Roller, from the Faculty of Pharmacy and Pharmaceutical Sciences Monash University, was the 2014 recipient of the PSA Lifetime Achievement Award.