What is a melanoma?
Melanoma is a cancer of the pigment-producing cells of the skin, known as the melanocytes. It is one of the most deadly of all cancers, not only of the skin, but of malignancies that can occur anywhere in the body. Contrary to popular belief, darker skinned people are not immune to developing these types of skin cancer.
In recent years, melanomas have become a major problem among South Africans and we have overtaken countries like Australia and New Zealand in the number of melanoma cases reported. Although melanomas are strongly linked to a family history and prolonged sun exposure, the exact cause of a melanoma, as is the case with many cancers, remains unknown.
Melanomas most often develop on the areas of the body where the skin has the greatest sun exposure. This includes the face, upper chest, back, arms and legs. It can also occur on the palms of the hands and soles of the feet. Despite the increased frequency on these areas, a melanoma can occur anywhere on the skin, even the areas that are covered by clothing.
Most of the time, melanomas look like a mole to the average person. A mole is a slightly raised dark brown blemish on the skin. It is harmless but a melanoma is not. There ma be itching, drying and scaling of the affected skin and in late stages even bleeding and oozing from the skin at the site of the melanoma.
Melanoma vs Mole
It is important to differentiate between a melanoma and a mole. Ideally, a person who is at risk should have an annual check up with a dermatologist or at least report any suspicious skin lesion to a dermatologist as soon as possible. However, many people delay and pass off a melanoma as a mole.
- Melanoma has an irregular shape whereas a mole is usually round to oval and symmetrical.
- Melanoma does not have clearly distinct border from the surrounding skin as a mole does.
- Melanomas may change in colour over time and become darker whereas the colour of a mole remains somewhat constant.
- Melanomas may grow into large lesions whereas melanomas usually do not extend beyond 6mm in diameter.
- Melanomas evolve over time by changing in size, shape and sensation whereas moles are relatively constant.
These five points are very important in differentiating between a melanoma and mole. It can easily be remembered as ABCDE – Asymetrical, Border, Colour, Diametre and Evolve. Remember that there are many different types of skin cancers. A melanoma is only one type. If in doubt about an abnormal skin growth, even if it does not have the characteristics of a melanoma described above, then you should see a dermatologist immediately.
What does a melanoma look like?
Picture of a melanoma from Wikipedia
Picture of a small melanoma from Dermatology Atlas Brazil.
Causes and Risk Factors
Melanocytes are the pigment-producing cells which are responsible for our skin, hair and eye colour. This is genetically determined. The melanocytes in darker-skinned people produce more of the pigment (melanin) while lighter-skinned people produce less pigment. Coupled with the blood flowing in the superficial skin vessels, skin texture and type, this accounts for why we all have different skin colours.
A melanoma occurs when something goes wrong with these pigment-producing skin cells. Normally our DNA contains the information which directs our cells to replicate when it is needed and grow in an orderly fashion so that the normal structure is maintained. But when this DNA is damaged or mutated, the skin cells grow abnormally. This is the reason for cancer anywhere in the body and in a melanoma, it is the melanocytes that grow abnormally.
A melanoma is a malignant tumour of the skin. Malignancy means that the tumour is cancerous. It will continue to grow if left untreated and invade and damage surrounding healthy tissue. It will also break away and spread to other parts of the body which is known as metastasis. Benign tumours on the other hand are normal cells that just become overgrown at a site and do not carry the risk of breaking away and spreading.
Who is at risk of skin cancer?
The exact reason why a melanoma occurs is unknown in every case. It is known that radioactive material, certain toxic drugs, ultraviolet light (mainly from sunlight) and genes inherited from parents may be responsible for skin cancers including malignant melanoma. It is also known that people living with HIV and AIDS patients are at a higher risk of developing cancers. However, other risk factors are not as clearly identifiable.
Melanoma and Sunlight
In recent years the issue about melanomas and sunlight exposure has come to the attention of South Africans. While these issues are not new, South Africans have been somewhat ignorant about the danger of sunlight and its link to developing melanomas. There has also been the perception that only Whites are at risk of developing this type of skin cancer. While a fairer skin does increase the risk, any person of any skin type and of any skin colour is at risk of developing a melanoma, particularly with prolonged sun exposure.
It is not the visible light that we see which is the problem in sunlight. It is the invisible ultraviolet (UV) light. Most of us known about UVA and UVB. It is this UV light that can damage the melanocytes and cause the development of skin cancer. People who have been sunburned several times in life, who spend long hours tanning and who work outdoors without adequate protection against the sun are at the greatest risk.
But ultimately every person who is exposed to sunlight, even for a few minutes in a day, is at risk of developing skin cancer. The risk in South Africa is greater than some other countries as we have more sunny days in a year and we tend to sunbathe with little understanding of the dangers. These are just some factors that increase the risk of sun exposure leading to melanomas among South Africans. Read more on skin cancer rises among black South Africans.
Tests and Diagnosis
Regular screening with a dermatologist should be considered a necessity if you are out in the sun a lot, either due to work or recreation, if you have a family history of melanoma or if you have previously had a melanoma or abnormal skin growths. This screening should be done on a yearly basis.
You should consult with a dermatologist immediately once you notice an abnormal skin growth even if it does not appear to be a melanoma. Although a melanoma may be suspected during a visual examination, the skin has to be examined under a microscope to confirm that it is indeed a cancer. Your dermatologist may take a sample of the skin, known as a skin biopsy, and send it for further examination by a pathologist.
A melanoma can be treated but this does not mean that it can be cured in ever case. Treatment and the success rate depends on the stage of the cancer. Staging will be done at the time of diagnosis to determine the best approach for treatment. Although staging can provide some indication of the survival rate, it is important to realise that there are many individual factors that can affect this rate.
Never be discouraged by survival rates, do not delay treatment and only consider alternatives once conventional medical treatment has been tried and your doctor approves considering other complementary routes.
The only treatment that can be considered to be curative in the very early stages is surgery. If the cancer along with the surrounding healthy skin can be surgically removed then the prognosis is very good. Nevertheless the cancer could recur. If the cancer has spread to lymph nodes or distant sites in the body then other treatment measures may also be needed beyond surgery.
Chemotherapy is the use of drugs that are toxic to cancer cells. It can be administered only at specific sites to destroy the cancer cells in that area or can be used to destroy cancer cells that are present at many sites in the body. It is important to remember that if there is metastasis (spread beyond the primary site), the prognosis is poor but chemotherapy can slow the progression of the cancer and ease the suffering of the patient.
In radiotherapy, high energy beams are used to destroy the cancer cells. These beams are directed at the specific site where the cancer is located and is done in a very controlled manner. Despite the fact that radiation can cause cancer, radiotherapy has been clinically proven to be effective in treating certain types of cancer to a certain degree.
Biological therapy and targetted therapy are other options for treating a melanoma. Biological therapy essentially harnesses the cancer-fighting ability of your own immune system to find and destroy cancer cells. Targetted therapy uses medication that will only affect certain types of cancer cells in the body.
Despite your best efforts, a melanoma cannot always be prevented. Therefore routine screening and early diagnosis are probably the best ways to ensure that a melanoma is not life threatening.
- Limit your time in the sun. About 20 minutes of continuous sun exposure already increases the risk of skin cancers especially if you experience many such episodes in your life. Depending on your location, as little as 10 minutes of sun exposure can be risky. Tanning beds use ultraviolet light to stimulate melanin production and can also be a risk for developing skin cancer.
- Avoid getting sun burnt. The more times you get sunburnt, the greater your risk of developing a melanoma.
- Use sunblock. Sun block lotions and creams are very effective measures of protecting the skin. A higher SPF (sun protection factor) means that it will protect you for longer that a lower SPF application. Try to apply the cream or lotion at least every 3 hours and the moment you come out of the water and dry off.
- Protective gear includes clothing, sunglasses and broad rim hats. Speak to your doctor about which fabric and lenses offer the best protection.
- Do not be fooled by weather and seasons. Ultraviolet light can still penetrate clouds in rainy weather and winter does not mean that the risk is lower. Adopt all protective measures throughout the year.
- Examine your skin regularly. In the same way that women are advised to examine their breasts regularly for cancer, all adults should examine their skin on regular basis to identify any abnormal skin lesions that could be the start of cancer.
For more information on melanoma and other skin cancers, refer to the South African Melanoma Advisory Board website and consult with your family doctor or a dermatologist as soon as possible.