If caught early, while it’s still only present in the skin, melanoma is a highly treatable disease, curable in approximately 95 to 98 percent of cases.
However, once melanoma metastasized, the 5-year survival rate is less than 15%, depending on which organs it has spread to.
What causes metastatic melanoma?
Anyone can get melanoma, but most cases of melanoma are caused by UV (ultraviolet) radiation from sunlight; some studies even put incidences of skin cancer caused by sun exposure at around 95%. The UV rays from the sun damage skin cells’ ability to repair DNA. When this happens, gene mutations can occur and the risk of cancer increases.
The risk of melanoma is higher in fair-skinned people as they have less melanin in their skin to protect from the sun’s rays. Risk is also higher if there is a history of melanoma in the family as gene mutations are often passed down from one generation to the next.
How does metastasized melanoma works
Melanoma begins in melanocytes cells (the cells that create pigment) in the deepest layer of skin. This is also known as the hypodermic or subcutaneous tissue. When these cells become damaged, mutations can occur and the mutated cells can reproduce themselves rapidly. Eventually, the cells start forming a tumor and taking over surrounding tissues.
Melanoma can develop from existing moles or skin growths, but, more commonly, they will start as new growth. In a further stage, it is possible that the melanoma grows into metastatic melanoma.
How melanoma moves from its original site
When a tumor gets too big, it requires more oxygen and nutrients to survive. This is when the tumor sends out signals that cause new blood vessels to grow into the tumor (a process called angiogenesis), bringing the nutrients and oxygen to it.
Read more about: What is melanoma?
After angiogenesis occurs, cancer cells are now able to break off and enter the bloodstream. They can also break off and spread through the lymphatic system (a system that carries fluid throughout the body and is a vital part of the circulatory and immune system). When this happens, the cancer cells can now settle and take root in a new area of the body.
According to the American Cancer Society, three things need to happen in order for the cancer cells to metastasize in a new area.
One: they need to attach to the wall of a blood or lymph vessel and move through it into a new organ.
Two: they need to have the necessary nutrients to grow on the new site.
Three: They must resist attacks from the immune system.
If the cancer cells manage to do all of these things, then a new tumor will develop. Typically, it will look slightly different from the cancer cells in the original tumor as a result of its journey.
Where melanoma is most likely to metastasize
According to an article published on Verywell by Timothy Di Chiara, Ph.D., a research scientist specialized in oncology, the likelihood that melanoma will metastasize to each organ is as follows:
- Lymph Nodes: 70-75%
- Other areas of the skin, fat, and muscle: 65-70%
- Lungs and area of the lungs: 70-87%
- Liver and gallbladder: 54-77%
- Brain: 36-54%
- Bone: 23-49%
- Gastrointestinal tract: 26-58%
- Heart: 40-45%
- Pancreas: 38-53%
- Adrenal glands: 36-54%
- Kidneys: 35-48%
- Spleen: 30%
- Thyroid: 25-39%
That being said, it’s important to note that melanoma can metastasize to almost every part of the body.
How to prevent metastatic melanoma
Learn the first symptoms of melanoma and symptoms of melanoma metastasis to stay on top of your health. Frequent skin self-checks and an understanding of what is normal for your body are essential for catching melanoma early before it starts metastasizing.