Melanoma is a serious form of skin cancer originating in melanocytes, the cells producing skin pigment. When these cancer cells break away from the initial tumor and travel to other body areas, this process is known as metastasis. This progression beyond the original site is called metastatic or advanced melanoma.
How Melanoma Spreads
Melanoma spreads through two main pathways: the lymphatic system and the bloodstream. The lymphatic system is a network of vessels and nodes that transport lymph, a fluid containing immune cells, throughout the body. Cancer cells can enter these lymphatic vessels, travel to nearby lymph nodes, and establish new tumors there. This often represents the first step in melanoma’s spread.
From the lymph nodes, or sometimes directly from the primary tumor, melanoma cells can enter the bloodstream. Once in the bloodstream, these cells can travel to distant organs and tissues, where they may form new tumors. This widespread dissemination makes metastatic melanoma challenging to treat.
General Signs of Advanced Melanoma
When melanoma spreads, it can cause general symptoms indicating advanced disease. Persistent fatigue is a common complaint, often described as an overwhelming lack of energy that does not improve with rest. Unexplained weight loss, often accompanied by a loss of appetite, can also occur. These systemic symptoms signal a more widespread presence of cancer within the body.
Symptoms Based on Spread Location
The specific symptoms of metastatic melanoma depend on where the cancer has spread within the body. These site-specific manifestations provide clues about the disease’s extent.
Lymph Nodes
When melanoma spreads to the lymph nodes, these nodes may become swollen, tender, or feel like hard lumps. These swollen nodes are often noticeable in areas such as the neck, armpit, or groin. In some cases, the enlarged lymph nodes can press on nearby tissues or nerves, leading to pain. Fluid accumulation, known as lymphedema, can also occur in the limb corresponding to the affected lymph nodes, for example, swelling in the arm if armpit nodes are involved.
Skin/Subcutaneous Tissue
Melanoma can also spread to other areas of the skin or to the subcutaneous tissue, which lies just beneath the skin. This spread may appear as new lumps or firm nodules on or under the skin, located away from the original melanoma site. These new growths can sometimes be flat, grey, or purple, and may occasionally bleed.
Lungs
If melanoma metastasizes to the lungs, individuals may experience a persistent cough that does not go away. Shortness of breath is another common symptom, which can range from mild to severe. Some people might also experience chest pain, and in more advanced cases, a cough that produces bloody sputum. Recurring chest infections or a buildup of fluid around the lungs (pleural effusion) can also indicate lung involvement.
Liver
Spread to the liver can lead to pain or tenderness in the upper right side of the abdomen, located under the ribs. Other symptoms include nausea and loss of appetite. Jaundice, characterized by a yellowing of the skin or eyes, can develop if the liver’s function is significantly impaired. Swelling in the legs or abdomen, known as ascites, may also occur due to fluid buildup.
Brain
When melanoma spreads to the brain, symptoms can include persistent headaches, which may be worse in the morning. Seizures are another potential symptom, as are changes in vision. Weakness or numbness on one side of the body can occur, depending on the affected brain region. Individuals might also experience changes in personality or mood, confusion, or memory problems.
Bones
Melanoma metastasis to the bones can cause persistent bone pain, often described as a gnawing sensation that worsens over time and may not improve with rest. This spread also increases the risk of fractures, which may occur with minimal trauma. If the cancer affects the bones of the spine, it can compress nerves, leading to back or neck pain, muscle weakness, numbness in the legs, or problems with bladder or bowel control. Elevated blood calcium levels (hypercalcemia) from bone breakdown can cause symptoms like dehydration, confusion, sickness, or abdominal pain.
When to Seek Medical Attention
Medical evaluation is recommended if you have a history of melanoma and experience any new or worsening symptoms. This includes general or specific symptoms related to potential organ involvement. It is also important to consult a doctor immediately if you notice any suspicious new growths on your skin or changes in existing moles. Early detection of melanoma spread allows for more treatment options and can improve outcomes. Regular follow-up appointments with a healthcare provider are also advised to monitor for any signs of recurrence or new melanoma.