Updated: October 27, 2006

General Information / Anatomy / Function / Statistics

• Not as frequent as basal cell or squamous carcinoma. (approximately 1 in 100 Canadians will get a melanoma)
• Increasing incidence in the last twenty years - mortality rates have increased in many countries
• Slowing increases in rates for younger cohorts (study groups)
• Most common sites are the back of men and leg of women
• Usually starts in pigment producing cells (melanocytes) in the skin, although it can arise in the eye and, uncommonly, other sites
• May start in an existing mole or in a new area
• Growth rate variable, but may be rapid and highly invasive
• Most aggressive or dangerous of all skin cancers
• Most are secondary to sun damage but melanomas can appear in unusual locations such as the nailbed of a finger, toe, nose or on the mucosa lining the inside of the mouth, vagina, or anus
• May travel by lymphatics or spread by the blood stream
• Most common sites for metastases are the lymph nodes, skin, lungs, brain, spinal cord, and liver; although they can spread anywhere in the body
• Melanomas can recur at the primary site if incompletely removed
• Overall cure rate for all treated melanomas is approximately 80%, ranging from 95%-100% for very superficial tumours, to 40% for tumours that penetrate through the skin into the fatty tissue underneath
• If regional lymph nodes are free of tumour, recurrence is much less likely than if they are involved
• It is extremely important that this type of cancer be detected in its earliest stages
• For statistics, please click here

• Diameter greater than 6 millimeters (larger than a pencil eraser) is cause for special attention
  • Particularly in a flat lesion
  • Sudden increase in size is of special concern
  • Darkening of an existing mole
  • Slow change is much more common
• Variation in colour
  • The pigmentation is not uniform, i.e. tan, brown, black can be present together
  • Special concern is the mixing of shades of red, white and blue
• Asymmetry
  • One half doesn't match the other half
• Border irregularity
  • Edges are ragged, notched, or blurred
• Change in mole surface (a late sign of melanoma)
  • Watch for scaliness, flaking, oozing erosion (as when a scab comes off), ulceration, bleeding
  • Appearance of a nodule or bulging, mushrooming mass
• Change in how a mole feels to the touch. (a late sign)
  • Getting hard
  • Getting lumps
• 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 pigmentation next to, but not a direct part of a mole)
• Onset of new feelings or symptoms in a mole
  • Itchy
  • Tender
  • Painful
  • Scaling
• Bleeding

Etiology / Carcinogens / Risks

• Originates in the pigment producing cells (melanocytes)
• A person who has developed one melanoma has an increased chance of developing more
• Patients who have been successfully treated must be monitored carefully
• Melanomas are most common in light-skinned people with freckles, and many moles
• In white women melanomas occur most often on the back and lower limbs; in white men on the trunk
• Exposure to sunshine increases the risk, particularly repeated or intermittent episodes of intense sun exposure in childhood
• Melanoma is most common in people in their forties to sixties
• Melanoma is rare before puberty
• Some moles called dysplastic nevi (atypical nevi), are more likely to become melanomas than others. Dysplastic nevi often appear larger than normal nevi (more than 5 mm across), often with irregularity of edge and variable color. Even though large in diameter, they are often quite flat.
• 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. All severe atypical nevi (dysplastic nevi) should be considered for surgical removal.

Prevention

• Examine your skin and your children's regularly for any changes in moles, freckles or skin discolorations
• Since people who have developed one malignant melanoma are at high risk for developing others, patients will be monitored closely and expected to take precautionary measures after the cancer has been successfully removed

Sunscreens

• The main objective of sunscreens is to prevent sunburn from UVB sunlight
• There is direct evidence available at present that sunscreens help to prevent squamous cell carcinoma skin cancer. There is insufficient evidence so far, indicating that sunscreens actually prevent basal cell or melanoma skin cancers.
• It is known, however, that sunburn occurring in childhood, adolescence, and post-adolescence contributes to a higher risk for basal cell cancer and melanoma 14 or more years later. This lag period may contribute to some confusion when studies are published which suggest that sunscreens do not protect against basal cell or melanoma skin cancers. Perhaps it is too early to show that sunscreens help to prevent basal cell or melanoma as the use of good sunscreens was not sufficiently prevalent until 10 years ago.
• There is no evidence that the active ingredients in sunscreens cause cancer in humans.
• Sunscreens are NOT intended to increase your exposure time but to increase your protection during unavoidable sun exposure.
• SPF indicates protection from UVB rays primarily.  Protection from UVA is provided by the following chemicals:
• • PARSOL 1789 (AVOBENZANE)
  • DIBENZOYLMETHANES
• List of sunscreens that are recognized by the Canadian Dermatology Association
• Complete physical block:
  • Zinc oxide
  • Titanium dioxide
• Use a water-resistant sunscreen if possible
• Do not apply oils to the skin. They usually increase the likelihood of a burn
• FAIR-SKINNED people should use a sunscreen that has an SPF of AT LEAST 30
• Use lip sunscreen or zinc oxide. Lip sunscreens include commercial products as well as lipstick
• Sunscreens are effective immediately upon application
• Use sunscreen liberally
• Re-apply sunscreen after swimming or significant sweating
• Sunscreen ingredients are effective for at least two years (check expiration date on package)
• Opaque sunblocks such as zinc oxide or titanium dioxide should be used if maximal sun exposure is contemplated (e.g., skiers, mountain climbers)
• For further help contact your dermatologist or pharmacist
• Patient follow up should include monthly self-examination and regular examination as arranged by his or her doctor
• Patients with a history of dysplastic nevi or a family history of melanoma may require more frequent visits. The patient's physician may recommend prophylactic removal of worrisome atypical (unusual) or dysplastic nevi from time to time. This can usually be done in the doctor's office under local anesthetic.
• Everybody, even if not in a high risk category, should avoid repeated extensive exposure to sun, wear protective clothing and use sunscreens with at least SPF 15, as described above

Diagnosis / Staging / Grading / Types

• Complete medical history will be taken with focus on skin problems, exposure to high-risk situations and family history of skin cancer or other types of cancer
• Complete physical examination with careful examination of the skin all over the body, including hard-to-see areas on the back, back of the neck, buttocks, genital area and scalp
• Diagnosis usually made on the basis of an excision biopsy (complete removal) which can be done in the doctor's office or outpatient clinic under a local anesthetic. If the lesion is quite large an incision biopsy (partial removal) may be done.
• Shave biopsies are not recommended as they do not allow assessment of the depth of invasion into the skin
• Cauterization or freezing should never be performed. These procedures destroy the superficial part of the melanoma, making diagnosis and staging impossible
• Laboratory tests include serum biochemistry and a chest X-ray.
• Special scans may be scheduled such as CT, ultrasound or lymphoscintiscan (radionuclide scan of local lymphatics)
• Microscopic examination determines the depth of invasion and is the best indication of risk. The melanoma may be referred to as "high risk" or "low risk".

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.
• Good cure rates (90% average ten year survival) are expected with melanoma depth of tumour less than 1.0 mm in thickness at diagnosis
• Moderate survival (65% to 78% average ten year survival) is seen with melanoma depth of tumour less 1.0 mm to 4.0 mm.
• Tumour invasion of local or regional lymph nodes reduces these rates.  Poorer survival (40% or less average ten year survival) is seen with melanoma depth of tumour greater than 4 mm at diagnosis.
• The BC Cancer Agency follows the American Joint Committee on Cancer (AJCC) Staging System for Melanoma.

Types

• 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 face of 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
  • Accounts for only a small percentage of all melanomas for light-skinned people
  • All types can grow and spread quickly
  • Occasionally there have been cases of spontaneous regression
  • Some regressions are partial - the original tumour goes away but the metastases continue to grow
  • Very rarely a complete spontaneous regression occurs

• Standard treatment for primary site is surgery
• The curative surgery is usually done after the biopsy
• The extent of recommended surgery for the primary site depends on the risk of recurrence
  • For relatively low risk melanomas the excision margin may be l cm or less and can often be repaired without skin grafting
  • Wider margins of up to 2 cm are often recommended for higher risk lesion. A skin graft is occasionally required
• Lymph nodes are not routinely removed in the absence of evidence of involvement.
• Radiation therapy can help shrink isolated large lesions or relieve pain
• Local or regional recurrences may be treated with surgery, radiation therapy, intralesional injection of agents such as BCG, or chemotherapy. The choice depends on individual circumstances.
• Although cure is still possible the risk of further recurrence is high
• Distant metastatic disease indicates spread via the bloodstream and systemic chemotherapy is usually the preferred treatment
  • The agent most frequently used is DTIC with an overall response rate of about 22%
  • Other agents may be suggested either alone or in combination
• Following treatment, patients should be monitored for life
• Recurrence, if it is to happen, usually appears within five years
• Active specific immunotherapy (melanoma vaccines) has shown some promise in treating advanced melanomas (experimental only)
• Interferon-alpha produces 10 to 20 percent response rate. However, there are many side-effects such as fever, chills, and fatigue. This is the first adjuvant treatment to receive U.S. FDA approval for malignant melanoma

Sun Tanning Parlours

• THE USE OF SUN TANNING PARLOURS IS STRONGLY DISCOURAGED!
• Tanning is a response of the skin to injury.
• Fluorescent sunlamps emit harmful ultraviolet radiation called "UVB". Some booths are advertised as "safe" because they emit a different kind of ultraviolet radiation called "UVA". But most of these UVA booths also give off UVB, the cancer causing part of the ultraviolet spectrum. Furthermore, there is some concern about the risk of UVA, which is associated with photoaging changes such as skin sagging.
• The following precautions apply to any type of tanning booth:
  You should not use a sun tanning booth or sunbed.  At particular risk are those who:
• Sunburn easily and don't tan. If you don't tan in the sun you probably won't tan in a booth.
• Get frequent cold sores. Ultraviolet radiation may aggravate their appearance.
• Some drugs increase your reaction to ultraviolet radiation
• Check with your doctor or pharmacist if you are taking prescription drugs.
• These drugs include but are not limited to:
• some antibiotics such as sulfas and tetracycline
• some high blood pressure medications
• some tranquilizers such as Librium
• diuretics (water pills)
• some birth control pills
• some oral diabetic medications
• The suntan provided by sunbeds/tanning booths is only minimally protective against a sunburn.  If you do go to a tanning parlour, continue to use a good sunscreen even after acquiring the artificial tan.  A tan does not completely protect you from harmful radiation.