Melanoma information

Melanoma is a malignant tumor of melanocytes. Melanocytes predominantly occur in the skin but can be found elsewhere, especially the eye. The vast majority of melanomas originate in the skin. Melanomas are the most lethal form of skin cancer. As with most forms of cancer, earlier detection gives patients a better chance of survival.

Epidemiologic studies from Australia suggest that exposure to ultraviolet radiation is one of the major contributors to the development of melanoma. This radiation causes errors in the Deoxyribonucleic Acid (DNA) of cells, making them go through Mitosis (cell division) at an unhealthy rate. Occasional extreme sun exposure (resulting in "sunburn") is causally related to melanoma. Those with more chronic long term exposure (outdoor workers) may develop protective mechanisms. Melanoma is most common on the back in men and on legs in women (areas of intermittent sun exposure) and is more common in indoor workers than outdoor workers (in a British study). Other factors are mutations in or total loss of tumor suppressor genes. Use of sunbeds (with deeply penetrating UVA rays) has been linked to the development of skin cancers, including melanoma.

Possible significant elements in determining risk include the intensity and duration of sun exposure, the age at which sun exposure occurs, and the degree of skin pigmentation. Exposure during childhood is a more important risk factor than exposure in adulthood. This is seen in migration studies in Australia where people tend to retain the risk profile of their country of birth if they migrate to Australia as an adult. Individuals with blistering or peeling sunburns (especially in the first twenty years of life) have a significantly greater risk for melanoma.

Fair and red-headed people are at greater risk for developing melanoma. A person with multiple atypical nevi or dysplastic nevi are at a significant risk. Persons born with giant congenital naevi are at increased risk.

A family history of melanoma greatly increases a person's risk. Certain 'melanoma families' display features of mendelian inheritance of cancer causing genes. It is critical that individuals with family members who have been diagnosed with melanoma be checked regularly for skin cancer. Patients with a history of one melanoma are at increased risk of developing a second primary tumour.

For most patients, regular skin self-exams and annual physician exams are sufficient to identify changes in moles that might indicate skin cancer. But some people have so many moles, or such a significant family history, that it’s hard to track potential changes. Please contact one of our physicians if you need help identifying potential problem areas.