Stage IV melanoma is a type of skin cancer that has metastasized, or spread, to other regions or organs in the body, such as the lungs, liver, brain, bone or lymph nodes, according to WebMD. Metastatic melanoma can also be found in the heart, spleen or digestive system.
Indications that the skin cancer has spread include swollen lymph nodes, bone pain, fatigue, liver swelling and difficulty breathing, reports WebMD. Headaches and seizures may be experienced, or a chronic cough may persist. Weight loss can occur, and there may be numbness of loss of strength in the extremities.
Melanoma severity is determined by assessing the extent of the spread, and this degree of severity is classified in four stages, using Roman numerals I through IV, explains Mayo Clinic. A melanoma classified as stage I is usually localized to the skin in one small area and is easy to treat. As the numerals assigned get higher, the chances of a full recovery lessen.
To determine the staging of a melanoma, the thickness is measured; a thicker tumor is indicative of a more severe cancer. A sentinel-node biopsy using contrast dye can help determine if the melanoma has spread to the lymph nodes adjacent to the cancer’s site, says Mayo Clinic. If an open sore is present in the location of the melanoma, or if actively dividing cancer cells are found in large numbers during the pathology review, the doctor can learn more about the aggressiveness of the melanoma’s progression.