What Is Melanoma

Melanoma is a type of skin cancer most commonly caused by damage to the DNA in a certain type of skin cells called melanocytes, often due to exposure to ultraviolet light. This damage can cause skin cells to form cancerous tumors, but if caught early it is almost always curable. However, if left untreated, melanoma can spread, or metastasize, to other parts of the body — such as the brain, bones, liver, and lungs.

When melanoma cannot be fully removed by surgery (stage III unresectable), or has metastasized (stage IV), it is known as advanced melanoma and is the most serious form of skin cancer. While overall metastatic melanoma survival rates have more than tripled since the 1970s, it is still one of the most difficult-to-treat cancers.


Advanced Melanoma (Unresectable or Metastatic) Facts and Figures

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Stages of Melanoma

Melanoma, like many cancers, is characterized into 4 main cancer stages based on the thickness of the cancerous tumor and how far it has spread. Doctors can determine the stage of melanoma by performing physical exams, including biopsies, as well as imaging tests such as CT or MRI scans. The 4 main stages of melanoma are:

stage 1
The cancerous tumor has formed within the skin but is small and is growing at a slow rate.
stage 2
The cancerous tumor, though localized, is considered intermediate melanoma as it is larger (generally over 1-millimeter thick) and/or growing at a faster rate than a stage I tumor. It has not been found in lymph vessels, lymph nodes, or distant organs.
stage 3 resectable
Resectable (removable) melanomas are cancerous tumors that have spread to lymph nodes, but can still be removed by surgery. There is no distant spread.
stage 3 non-resectable
Unresectable (unremovable) melanomas are cancerous tumors that have spread beyond the skin to the lymph nodes, and surgery may not be able to remove all of the cancer. There is no distant spread.
stage 4
Also known as metastatic melanoma, it means the melanoma has metastasized, or spread, to lymph nodes that are distant from the primary cancerous tumor, or to organs, such as the lungs, liver, brain, or bones.

Despite these staging definitions, not all advanced melanoma (unresectable or metastatic) is the same. Patients may have different genetic changes present in their tumor, also called mutations, making their disease uniquely personal.