Five key factors help to determine how serious melanoma is:
Tumor thickness — How deep it goes into the skin.
Location — Melanoma on the arms or legs may not be as serious as a tumor somewhere else on the body.
Age — People older than 60 are in more danger.
Gender — Males are more likely to die of the disease.
Spreading of the tumor — Twenty percent of people with melanoma have cancer in lymph nodes when their cancer is diagnosed.
The thickness of the tumor is the most important factor in determining whether it can be treated. Tumors on the skin's surface usually can be cured. Deeper cancers are more difficult, sometimes impossible, to treat. If melanoma cells break away and spread to organs such as the lungs, liver or brain, the cancer can be cured in only a small number of patients.
If treatment begins when the tumor is less than 0.75 millimeters deep, the chance of a cure is excellent. More than 95% of people with small melanomas are cancer-free as long as 8 years later. However, for deeper melanomas, the survival rate is poor. Fewer than half of people with tumors thicker than 4 millimeters survive for 5 years. If melanoma cells are found in a lymph node, the 5-year survival rate is between 30% and 50%.