What Is Metastatic Melanoma?
No one is ever prepared to hear they have any type of cancer, particularly not melanoma, the most dangerous form of skin cancer. This type of cancer forms in the cells that give color to your skin, called melanocytes. It frequently develops around pigmented tissue, which means on or around moles, but it can also form on clear expanses of skin and even in the eyes. Metastatic melanoma is melanoma that has spread to other parts of your body. It’s also commonly referred to simply as stage four melanoma.
The spreading for melanoma occurs through the lymphatic system and/or the blood vessels. After the cancer develops, it ultimately spreads to the lymph nodes, the deeper levels of tissue under your skin and to various organs like the brain, liver, lungs and bones. To achieve the best possible treatment outcome with melanoma, it’s important to spot the disease early. Let’s take a look at what you need to know about the causes, symptoms, diagnosis and treatment of metastatic melanoma.
What Causes Melanoma?
Generally, exposure to ultraviolet (UV) radiation from the sun or tanning beds causes melanoma. UV rays damage the DNA of skin cells and cause them to grow irregularly. However, it’s important to note that you can actually develop melanoma on body parts that don't get as much direct sunlight like the palms of your hands and your retinas in your eyes.
Various risk factors contribute to your chance of developing melanoma. According to the American Cancer Society, nearly 10% of individuals who develop melanoma have a family history of the disease. Fair or light skin and numerous irregular moles are other risk factors that could make you more susceptible to developing this type of skin cancer.
Additionally, there is a higher risk of melanoma in people who have a suppressed immune system, and the risk of metastatic melanoma increases when visible primary melanomas haven’t been removed. This type of cancer becomes more common with age, but it occurs in younger people as well.
What Are the Symptoms of Melanoma?
Melanoma symptoms depend on if and where the cancer has spread. Many symptoms won’t occur until the advanced stages of the disease, which is why it’s important to recognize physical abnormalities and changes in moles and other skin marks as soon as they occur. Unusual moles appearing on your skin could indicate a melanoma that hasn't yet metastasized. Suspicious moles could have irregular borders, be more than one color, be larger in size or be asymmetrical.
If you develop metastatic melanoma, you may experience symptoms like weight loss, fatigue, headaches and weakness in your legs or arms. You could have seizures if it spreads to your brain. Painful or swollen lymph nodes and hardened lumps underneath your skin are also associated with this disease. If the tumor spreads to your liver or stomach, you could experience an enlarged liver and loss of appetite. If it spreads to your lungs, you could experience difficulty breathing.
How Is Metastatic Melanoma Diagnosed?
Diagnosing melanoma involves an excisional biopsy, where a dermatologist removes a sample from a suspicious mole or spot to check for skin cancer. If the test comes back positive, then the doctor will completely remove the mole and a certain amount of surrounding tissue. Additional testing will be necessary to determine if the melanoma has spread to your lymph nodes. These tests include a sentinel node biopsy, computed tomography (CT) scans, blood tests and magnetic resonance imaging (MRI) scans.
How Is Metastatic Melanoma Classified?
The spread of melanoma can be categorized into four groups: local recurrence, hematogenous spread, nodal metastasis and in-transit metastasis. Local recurrence involves a tumor regrowth of the primary melanoma within 2 centimeters of the surgical scar from the removal of a former melanoma. It's caused by primary melanoma extending to other areas or spreading through the lymphatic vessels.
Hematogenous spread occurs when a tumor invades the blood vessels and involves the lymph nodes and secondary melanoma. This can lead to metastases in other organs like the heart, adrenal glands, bones and kidneys.
Nodal metastasis occurs when the primary tumor spreads to other areas of the body via the lymph nodes. The regional lymph nodes are the first to enlarge and can usually be felt. In-transit melanoma metastasis also involves the spread of skin cancer through a lymph vessel, but this cancer starts to grow more than 2 centimeters away from the primary tumor before reaching the nearest lymph node.
How Is Metastatic Melanoma Treated?
Melanoma treatment starts with the removal of the tumor and all the surrounding cancerous cells through excision surgery. If metastatic melanoma is found in the lymph nodes, your doctor will recommend lymph node dissection to remove the affected tissue. After surgery, interferon therapy is common to reduce the chance of the cancer spreading to other parts of the body. Radiation, surgery, chemotherapy and immunotherapy are also used to treat metastatic melanoma, particularly when it has spread beyond the lymph nodes to other organs.