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Melanoma

This information should not be used for self-diagnosis or in place of a qualified physician's care.

Reviewed Dec 2016

The basics
  • Guidelines for treating this cancer have been developed by the Skin Tumour Group.
  • For health professional information on treating this cancer, please see our Cancer Management Guidelines.
  • Cancers of the skin are also known as cutaneous cancers or dermatological cancers.
  • Melanoma is a type of skin cancer and is the most aggressive or dangerous of all skin cancers.
  • For the more common skin cancers called Basal Cell Carcinoma and Squamous Cell Carcinoma, see Skin Cancer – Non-Melanoma.
  • Another cancer that affects the skin is Skin Lymphoma.
  • Skin keeps moisture inside the body and repairs and renews itself as millions of dead skin cells are lost each day. The skin is also the outermost limit of the immune system.
  • The skin consists of two layers: the outer epidermis and the supporting dermis. The dermis is made up of connective tissue, blood vessels, and nerves. Together the epidermis and the dermis contain hair follicles, sweat glands, sebaceous glands and nerve endings.
  • New skin cells are produced in the bottom layer of the epidermis called the basal layer, just above the dermis.
  • The epidermis also contains melanocytes, the cells which produce melanin, the pigment responsible for skin colour.
  • Cutaneous (skin) malignant melanoma originates in the melanocytes which are the cells in the epidermis which produce melanin, the pigment responsible for skin colour. Moles, or nevi, are not usually cancers.
  • Melanocytes also exist in the eye. For ocular melanoma, see Eye cancers.
  • Melanoma of the skin may start in an existing mole (nevus) or in a new area.
  • It is extremely important that this type of cancer be detected in its earliest stages. The growth rate is variable but may be rapid and melanoma is highly invasive.
  • Melanomas can recur at the primary site if not completely removed.
  • Melanoma may spread (metastasize) by way of the lymph system or the blood stream.
  • If regional lymph nodes are free of tumour, recurrence is much less likely than if they are involved.
  • The most common sites for metastases are the lymph nodes, skin, lungs, brain, spinal cord, and liver, although it can spread anywhere in the body.
  • Superficial melanomas can be cured, but tumours that spread through the skin into the fatty tissue underneath are less able to be cured.
What causes it and who gets it?
Some of the known risk factors for this cancer are listed below. Not all of the risk factors below may cause this cancer, but they may be contributing factors.

  • Too much exposure to ultraviolet (UV) light, which is a type of radiation, causes damage to the skin. Damage includes sunburn, wrinkles, and aging. Tanning is a response of the skin to injury.
  • Exposure to sunshine increases the risk of skin damage, particularly repeated episodes of intense sun exposure in childhood.
  • UV light from sun tanning beds also causes skin damage.
  • Melanomas are most common in light-skinned people with freckles and many moles.
  • Melanoma is most common in people in their forties to sixties and is rare in children.
  • In white women melanomas occur most often on the back and legs; in white men on the back and trunk.
  • A person who has developed one melanoma has an increased chance of developing more. Patients who have been successfully treated must be monitored carefully.
  • Most melanomas are secondary to sun damage, but they can appear in unusual locations such as the nailbed of a finger, toe, nose or on the mucus lining the inside of the mouth, vagina, or anus.
  • Some moles called dysplastic nevi (atypical nevi) are more likely to become melanomas than others. Dysplastic nevi often appear larger than normal moles (more than 5 mm across), often with irregularity of edge and variable colour. Even though large in diameter, they are often quite flat.
  • Individuals who have a strong family history of melanoma (two or more first degree relatives with the disease) may carry a particular genetic mutation and have "atypical nevus syndrome," also called "dysplastic nevus syndrome."
  • Statistics
Can I help to prevent it?
  • Protect your skin from the sun and other sources of ultraviolet (UV) light.
  • Avoid sunburn, particularly in children.
  • Limit time in the sun, especially between 11am and 3 pm.
  • Cover up by wearing long sleeves, pants and a hat with a wide brim.
  • Be aware that some drugs increase your reaction to ultraviolet radiation. Check with your doctor or pharmacist if you are taking prescription drugs.
  • Use sunscreens.
    • Use a sunscreen that is labeled "broad-spectrum" with an SPF of at least 30.
    • Sunscreens are not intended to increase your exposure time but to increase your protection during unavoidable sun exposure.
    • A list of sunscreens currently recognized by the Canadian Dermatology Association is available.
    • Sunscreen ingredients are effective for at least two years (check expiration date on package). There is no evidence that the active ingredients in sunscreens cause cancer in humans.
    • For a complete physical block, opaque sunblocks such as zinc oxide or titanium dioxide should be used if extreme sun exposure is likely (e.g., skiers, mountain climbers).
    • Protect the lips with lip sunscreen or zinc oxide.
    • Do not apply oils to the skin. They usually increase the likelihood of a sunburn.
  • Avoid tanning beds, tanning salons and sunlamps.
    • The use of sun tanning beds and sunlamps is strongly discouraged because they give off UV radiation that cause skin damage.
    • B.C. has banned commercial tanning bed use by young people under the age of 18 to reduce the chances of developing skin cancer later in life.
    • The suntan provided by sunbeds/tanning booths is only minimally protective against a sunburn. If you do go to a tanning salon, continue to use a good sunscreen even after you have an artificial tan. A tan does not completely protect you from harmful radiation.
  • The BC Cancer Agency's Prevention Programs offer more advice on preventing skin cancers for people of all ages.
Screening for this cancer
  • Screening for melanoma is not generally available for the population as a whole.
  • Check your skin and your children's skin regularly for any changes in moles, freckles or skin discolourations and bring them to your doctor's attention.
  • To do a skin cancer self-exam and for tips on what to look for, see:
    5 Steps to Skin Cancer Self-Exam and ABCDEs of Melanoma.
  • Screening of high risk individuals to find melanoma early is very important. More people survive when melanoma is found before it grows deep into the skin or spreads.
  • Persons who have had a previous melanoma should be examined regularly by a physician, ideally a dermatologist.
  • Persons who have a strong family history of melanoma should be examined regularly by a physician, ideally a dermatologist.
  • Certain families are prone to develop dysplastic nevi and once a family member is identified as having one such nevus, other family members should have their moles examined by their doctor.
  • The doctor may recommend preventative removal of worrisome or unusual moles from time to time. This can usually be done surgically in the doctor's office under local anesthetic.
Signs and symptoms
  • Any nevus or mole that has significant changes in shape or colour, or a mole that causes symptoms of itching or burning, should be suspected to be a melanoma.
  • The acronyms ABCD (see Melanoma) or ABCDE refer to features that are used to identify those moles and skin lesions that require a biopsy to rule out melanoma:
  • Asymmetry.
    • One half doesn't match the other half.
  • Border irregularity.
    • Edges are ragged, notched, or blurred.
  • Colour variation.
    • The pigmentation is not uniform, i.e. tan, brown, black can be present together.
    • A special concern is the mixing of shades of red, white and blue.
  • Diameter greater than 6 millimeters (larger than a pencil eraser) is cause for special attention.
    • Particularly in a very flat mole
    • Sudden increase in size is of special concern.
    • Darkening of an existing mole.
    • Slow change is much more common.
  • Evolution, or changes in mole surface, shape, feel, or surrounding skin.
    • Watch for scaliness, flaking, oozing erosion (as when a scab comes off), bleeding.
    • Appearance of a nodule or bulging, mushrooming mass.
    • Changes in how a mole feels to the touch.
    • Getting hard or lumpy.
    • Change in shape or outline of a mole.
    • Finding an irregular, notched border where it used to be regular and smooth.
    • Sudden elevation of a surface that used to be flat.
    • Change in skin around a mole.
    • Spread of pigment from the edge of the mole into the skin that used to be normal looking.
    • Finding redness or swelling (inflammation).
    • A very late sign is the development of satellite pigmentation (that is, nodules of colour next to, but not a direct part of a mole).
    • Onset of new feelings or symptoms in a mole, if it becomes itchy, tender, or painful.
Diagnosis & staging
Diagnosis
These are tests that may be used to diagnose this type of cancer.

  • Complete medical history with a focus on skin problems, exposure to high-risk situations and family history of skin cancer or other types of cancer.
  • Complete physical examination, including a careful examination of the skin all over the body, hard-to-see areas on the back, back of the neck, buttocks, genital area and scalp.
  • Excision biopsy (complete removal and examination of a small bit of tissue). This can be done in the doctor's office or outpatient clinic under a local anesthetic. If the skin lesion is quite large an incision biopsy (partial removal) may be done.
  • Serum biochemistry (blood test).
  • Chest X-ray.
  • CT scan.
  • Ultrasound.
  • Lymphoscintiscan (scan of nearby lymph nodes).
For more information on tests used to diagnose cancer, see our Recommended Links, Diagnostic Tests section.

Types and Stages
Types
  • Melanomas may be classified into several types, all of which can grow and spread quickly.
  • Superficial spreading melanoma (SSM)
    • Accounts for two-thirds of all melanomas
    • May start from a pre-existing mole (dysplastic nevus)
  • Nodular melanoma (NM)
    • A nodule appears, usually unrelated to a pre-existing mole
  • Lentigo maligna melanoma (LMM)
    • Less common
    • Occurs most commonly on the sun-exposed faces of the elderly
  • Acral lentiginous melanoma
    • Occurs in the palms or the soles or under the nail beds
    • Accounts for the majority of malignant melanomas for dark-skinned people but for only a small percentage of all melanomas for light-skinned people
Stages Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

T describes the site and size of the main tumour (primary)

N describes involvement of lymph nodes

M relates to whether the cancer has spread (presence or absence of distant metastases) 

For a chart of the current TMN classification for melanoma, see Staging.

  • Early detection of melanoma is of vital importance as survival is directly related to the depth of tumour invasion at diagnosis and whether the local or regional nodes are positive.
Treatment

Treatment

Cancer therapies can be highly individualized – your treatment may differ from what is described below.

Surgery
  • Standard treatment for the primary site of melanoma is surgery.
  • Surgery to cure melanoma is usually done after a biopsy.
  • For relatively low risk melanomas, the excision margin (area removed by surgery) may be 1 cm or less and can often be repaired without skin grafting.
  • Wider margins of up to 2 cm are often recommended for higher risk lesions. A skin graft is sometimes required.
  • Lymph nodes are not routinely removed if there is no evidence of involvement.
Chemotherapy Radiotherapy
  • Radiation therapy may be used after lymph node dissection (removal).
  • Radiation therapy may help shrink isolated large cancers.
Treatment for recurrent, metastatic or advanced melanoma
  • Recurrence, if it is to happen, usually appears within five years.
  • Although cure is still possible, the risk of further recurrence is high.
  • Local or regional recurrences may be treated with surgery, radiation therapy or chemotherapy. The choice depends on individual circumstances.
  • Distant metastatic disease, when the melanoma has spread to other parts of the body, is usually treated with chemotherapy.
  • Radiation therapy may be used to relieve pain or control other symptoms.
Follow-up after treatment
  • Guidelines for follow-up after treatment are covered on our website.
  • You will be returned to the care of your family doctor or specialist for regular follow-up. If you do not have a family physician, please discuss this with your BC Cancer Agency oncologist or nurse.
  • Follow-up testing is based on your type of cancer and your individual circumstances.
  • Life after Cancer focuses on the issues that cancer survivors can face.
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