The facts on skin cancer and melanoma

Here are some facts on skin cancer and melanoma:

  • There are three main types of skin cancer, all strongly related to sun exposure, and all extremely common in Australia.
  • The first two, are the most common forms of skin cancer, squamous cell carcinomas and basal cell carcinomas
  • Each year more than 374,000 people in Australia are diagnosed with the: basal cell carcinoma and squamous cell carcinoma.
  • These two diseases are the least life-threatening and fortunately are very slow to spread. there are ways to prevent most non-melanoma skin cancers and to detect them early when they do arise treated before they have a chance to threaten function and life. When treated early, the vast majority of these cancers are curable.
  • Most people who are diagnosed with non-melanoma skin cancers are age 50 or older, but because these diseases often are a result of too much exposure to the sun, everyone — even the youngest toddlers — should take precautions against them.
  • Melanoma, which arises in the same cells in the skin that give rise to moles, is the most aggressive form of skin cancer, and one of the most aggressive of all types of human cancer. It is now the second most common cancer in men and women in NSW.
  • Melanoma – is more common in Australia than any other country. The melanoma incidence rates in Australia and New Zealand are around four times higher than those found in Canada, the UK and the US and up to ten times higher than in other countries.

  • Melanoma causes more productive years of life lost than most cancers because there are a large number of people affected in earlier life.
  • Melanoma risk is highest in the lower latitude areas where there are high levels of ambient UV.
  • Excluding melanoma, Tasmania has the highest incidence rate for all cancers combined and the highest mortality rates for both males and females while NSW has the lowest mortality rates.
  • Most melanomas are treatable if detected early However, mortality rates for melamona in Australia are quite low compared to other countries.
  • In Denmark each year, there are approximately 13,000 new cases of skin cancer diagnosed: 12,000 are non-melanoma basal cell carcinoma and squamous cell carcinoma cancers, seen mostly in elderly people. The remainder are melanomas, and most often this cancer strikes young people between 20 and 30 years old
  • Over 90% of all cases of skin cancer in Denmark sun responsible for all cases of skin cancer, perhaps because of the impact of exposure to ultra-violet light in people with the northern hemisphere fair skin type.

Causes

  • Australia has an incidence many times higher than most other Western countries, and this is thought mainly to be due to very high levels of environmental ultra-violet light exposure in people with northern fair skins.
  • Ultraviolet (UV) radiation is the single most important cause of skin cancer, especially when the overexposure resulted in sunburn and blistering. Other, less common causes of skin cancer include repeated exposure to x-rays and exposure to coal tar, arsenic, and other industrial compounds.

High-risks

  • The lifetime melanoma risk for the average Australian is about one in 25. However, a combination of genetics, environment, and lifestyle can make the development of melanoma much more common in some people.
  • The main risk for getting melanoma seems to be episodic severe sunburning in childhood and teenage years
  • People who sunburn easily and tan poorly, people with a family or personal history of melanoma, and those with weakened immune systems are at higher-than-average risk for developing melanoma
  • Sunlight provides much that is beneficial and even necessary to life and good health. Tanning and burning, however, are not among those benefits — there is no such thing as a “healthy tan.”
  • Although it’s clear that UV radiation can damage DNA, and that high levels of sun exposure are associated with melanoma risk, the exact relationship between UV exposure and melanoma remains unclear.
  • Over the past decade, researchers have discovered that the tanning response begins only after DNA in skin cells has been damaged by exposure to sunlight.
  • Other, less common causes of skin cancer include repeated exposure to x-rays and exposure to coal tar, arsenic, and other industrial compounds.
  • Although the exact wavelengths and timing of the solar radiation associated with different types of skin cancer are under investigation, the basic preventive lesson remains the same: protect your skin from the sun.

Skin Types

  • It is interesting to note that human beings almost certainly all started off with black skins, but as they migrated to areas with low sunlight, they evolved to have fairer skins because this gave them the advantage of being able to make vitamin D under conditions of lower sunlight exposure. Vitamin D is activated in the skin under the influence of sunlight and is essential for bone health.
  • Such changes in skin colour take place over millions of years, and the descendants of the Caucasian people who migrated to Australia in the 18th and 19th centuries obviously still have the fair skin of their ancestors which means that they generally tan poorly, and burn easily.

Treatment of Melanoma

  • Melanoma is usually treated with surgical removal of the primary tumor.
  • Melanoma cells tend to invade the blood stream, migrate, and lodge in distant organs such as the liver, lung and brain, where they form secondary tumours that are often untreatable.
  • Treatment of more advanced melanoma could involve radiation therapy, chemotherapy, and immunotherapy.
  • Secondary or “metastatic” melanoma occurs commonly in young adults, and fewer than 5% of people with metastatic melanoma survive two years.
  • As yet we have no effective drug treatments and most medical care is directed towards comfort and palliation.

Basal cell carcinoma

  • The most common cancer in humans worldwide.
  • Basal cell carcinomas are most often found on the face, neck, hands, or other parts of the body that have been exposed to the sun.
  • Overexposure to ultraviolet (UV) radiation is the single most important cause of skin cancer, especially when the exposure resulted in sunburn and blistering.
  • This type of cancer can have many different appearances: a red patch or irritated area; a small, pink pearly bump; a white or yellow scar-like area; a smooth growth with a dent in the center; or an open sore that bleeds or oozes.
  • Basal cell carcinomas rarely spread throughout the body and deaths from them are very rare; however, because they often occur on the face, their locally destructive effects can result in serious cosmetic deformity if not diagnosed and treated early.
  • Basal cell carcinomas are highly curable with both surgical and non-surgical therapy. Treatment options may include curettage and electrodesiccation, radiation therapy, standard excision, and other individualized approaches.

Squamous cell carcinomas

  • Squamous cell carcinomas account for about 20 percent of skin cancers in Australia and have an excellent cure rate when detected early.
  • They arise from the upper levels of the epidermis, usually on places that have been exposed to the sun.
  • Squamous cell carcinomas are most commonly found on the ears, the face, and the mouth. They tend to occur in people who are slightly older than those who get basal cell tumors.
  • Often it comes from a precancerous lesion known as keratosis (sometimes called solar keratosis), which appears as a rough, flat pink spot. If the lesion becomes cancerous, it is raised above the normal skin surface.
  • Squamous cell tumors tend to be more aggressive than basal cell tumors, and are slightly more likely to spread to other parts of the bod
  • Most squamous cell carcinomas can be cured with minor surgery. Treatment options may include curettage and electrodesiccation, radiation therapy or standard excision.
  • Overexposure to UV radiation (UVB radiation in particular) is the most common risk factor associated with squamous cell carcinoma.
  • Exposure to ultraviolet (UV) radiation is the single most important cause of skin cancer, especially when the exposure resulted in sunburn and blistering.

Sources

Professor Richard Kefford, Westmead Millenium Institute

Memorial Sloan-Kettering Cancer Centre website at http://www.mskcc.org/mskcc/html/390.cfm

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