NCCN Guidelines for Patients
Part 1: About melanoma
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1.3 How melanoma spreads
Unlike normal cells, cancer cells can spread to other parts of the body.
This process is called metastasis. The uncontrolled growth and spread
of cancer cells makes cancer dangerous. Cancer cells can replace or
deform normal tissue causing organs to stop working.
Cancer cells often spread to nearby and distant sites through lymph or
blood. Lymph is a clear fluid that gives cells water and food. It also has
white blood cells that fight germs. Lymph nodes filter lymph and remove
the germs. Lymph travels throughout the body in vessels like blood
does. Lymph vessels and nodes are found everywhere in the body
(Figure 4). Once melanoma has grown into the dermis, it can reach the
Cancer that spreads to a nearby body part is called a local metastasis.
Cancer that has spread to a body part far from the primary tumor is
called a distant metastasis. Melanoma that has spread into nearby
lymph vessels, but not to lymph nodes, is called in-transit metastasis
or in-transit disease. Melanoma that has spread to a small area of skin
near the first tumor is called satellite metastasis or satellite disease.
Figure 4. Lymph nodes and vessels
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