Malignant melanoma is the most deadly of all skin cancers. Over 5,000 people are diagnosed annually in Canada. Melanoma causes more than 900 deaths every year. Early diagnosis is the key to positive outcomes
What does it look like?
Melanoma can start as a new, brown or black, flat, freckle-like spot on the skin’s outer surface. It can also begin as a change in the shape or colour of an existing mole or coloured spot. Melanomas tend to be dark in colour — browns and blacks — although some are a mixture of colours including red, blue and white. These tumours grow, so the key is to look for changes.
What causes it?
While the full answer still has not been unravelled, what is sure is that excessive exposure to ultraviolet radiation (ie. sunlight and tanning beds) plays a leading role in the development of this type of skin cancer. Severe, blistering sunburns especially in childhood are thought to play an initiating role. However, recent research shows that sunburns at any time during life can also increase the risk.
Indoor tanning is also a known risk of melanoma.
Who is at highest risk?
While anybody can get melanoma, fair skinned people who have sun-sensitive skin that burns rather than tans are more likely to get this disease. People with freckles and red hair fall into this group, as do some blonds and those with blue or green eyes. Those with many moles (more than 50), or moles with an unusual colour or shape, or with large moles, have an elevated risk. A close family history of melanoma is another risk factor. Anyone with one of more of these risk factors should have a spot check by a dermatologist — it could prove to be a life-saving visit. People with no risk factors at all may still get melanoma.
Where does it often appear?
Melanoma appears most commonly on the backs of men and legs of women. However, it can appear anywhere on the skin surface or in the mouth or eyes. While less common in darker skinned people, melanoma usually appears on the palms of hands, soles of feet and nail beds in these people.
How long does it take to develop?
Melanoma can develop within weeks or months or it can be slow growing over several years.
Is there any way to prevent the disease?
Protect young children from the sun. Avoid the sun from 10 am to 4 pm (or during the most intense times of sun exposure depending where you live) and protect yourself if outside during these times by seeking shade, covering up with clothing and wide brimmed hats. Wear a broad-spectrum sunscreen with a minimum SPF of 30. Apply before you leave the house and reapply every two hours or more frequently during strenuous exercise or after swimming. Look for the Canadian Dermatology Association logo on sunscreen products to ensure these are safe and effective.
Avoiding the use of indoor tanning beds will also reduce your risk of melanoma and regular skin check (monthly self-examinations and annual physician checks are recommended) will increase the probability of early diagnosis.
Stages of Melanoma
- Stage 0 – Only in the very top layer of the skin (the epidermis).
- Stage 1 – Is in the surface layers of the skin and has not spread to nearby lymph nodes; is smaller than 1 mm with or without ulceration OR between 1 and 2 mm without ulceration.
- Stage II – Is in the surface layers of the skin and has not spread to nearby lymph nodes; is between 1 and 2 mm with ulceration OR is larger than 2 mm with or without ulceration.
- Stage III – Has spread within the skin or to at least one nearby lymph node.
- Stage IV – Has spread to other skin areas, to distant lymph nodes or to other parts of the body including internal organs such as the lung.