Late-stage melanoma - the most aggressive form of skin cancer - can spread (metastasize) through the bloodstream from its original location to the brain and other parts of the body. This occurrence is known as skin cancer metastasis, metastatic skin cancer or metastatic melanoma.
Several cancers can metastasize from their original site to the brain, the most common being lung and breast cancers, followed by melanoma. In these instances, the original cancer is referred to as the primary cancer, while the metastasis is known as the secondary cancer or tumor. Secondary brain “tumors” that originate from melanoma are actually masses of skin cancer cells.
What are the symptoms?
The telltale symptom of primary melanoma is a new or unusual mole on the skin that may:
- Be asymmetric
- Have an irregular border
- Have multiple colors
- Be large or grow bigger
Many patients with skin cancer metastases in the brain don’t experience symptoms that would suggest the skin cancer has spread. When metastatic melanoma symptoms do occur, they can include:
- Vision problems
- Paralysis that affects one side of the body
- Swollen, painful lymph nodes
- Nausea or vomiting
- Weakness and fatigue
Experiencing symptoms may indicate that there is a large secondary tumor or multiple lesions in the brain.
Are there risk factors?
Melanoma itself is caused by mutations in skin cells that produce melanin (melanocytes). A major risk factor for melanoma is frequent exposure to ultraviolet (UV) rays from the sun or tanning beds. Having very pale skin or a family history of melanoma can also increase an individual’s risk of skin cancer.
Additionally, certain factors can increase the risk of melanoma spreading to the brain. These include:
- Primary skin cancer that is not treated or removed
- Primary skin cancer located on the trunk, abdomen, neck or head
- Primary skin cancer that is invasive or ulcerated
- Having a compromised immune system
- Having an NRAS or BRAF gene mutation
More than 60% of all patients with stage 4 melanoma will eventually develop metastases in the brain, according to the AIM at Melanoma Foundation.
How is it diagnosed?
Diagnosing melanoma is a relatively straightforward process that involves excising a portion of a mole and testing it for cancerous cells. Diagnosing skin cancer metastasis in the brain, however, is more complex. There are several tests that may be used if a physician suspects that melanoma has spread to the brain:
A neurological exam
A neurological exam can involve evaluating various health characteristics, including reflexes, balance, coordination, vision and more. The results of this exam may shed light on what area of the brain is affected, if the melanoma has metastasized.
An MRI scan
A magnetic resonance imaging (MRI) scan produces images that can show if cancerous lesions are present in the brain. Other imaging techniques, such as computerized tomography (CT) scans and X-rays, may be used to see if melanoma has traveled elsewhere in the body.
A biopsy may be performed to definitively diagnose a secondary brain tumor, although this is not always necessary. Obtaining a sample of abnormal tissue for testing may involve surgery or drawing out cells using a needle.
What are my treatment options?
Recent advancements in cancer treatment have significantly improved outcomes and quality of life for patients with skin cancer metastases in the brain. Some cases of metastatic melanoma are curable. In other cases, treatment may focus on relieving symptoms and helping patients live longer.
There are several factors that will influence a patient’s metastatic melanoma treatment options. These include the:
- Patient’s age (notably, if the patient is younger or older than 60)
- Patient’s overall health
- Number and specific location of brain lesions
- Patient’s care preferences
Based on these factors and more, a metastatic melanoma treatment plan may involve:
Surgery is the primary form of treatment for melanoma in the brain. It may be performed to:
- Remove a tumor
- Remove a portion of a tumor that cannot be fully excised
- Help reduce symptoms and improve quality of life
Surgery is usually followed by radiation therapy or medications to address cancer cells that cannot be surgically removed.
Multiple forms of radiation therapy can be used to treat skin cancer metastases in the brain, either by attacking cancer that is too small to be visible or by shrinking tumors that cannot be surgically removed. During radiation therapy, a high dose of cancer-fighting radiation is delivered to precise areas of the brain.
Breakthrough medications including gene-targeted therapies and immune checkpoint inhibitors are helping patients live longer. Gene-targeted therapies work by impeding the processes that contribute to cancer growth, while immune checkpoint inhibitors help the patient’s immune system identify and attack cancer. Other immunotherapies for brain metastases and leptomeningeal disease are being developed.
Our approach to skin cancer metastasis
Patients at Moffitt Cancer Center’s Cutaneous Oncology Program and Neuro-Oncology Program benefit from the combined expertise of a multispecialty team that focuses exclusively on skin cancers, including melanoma in the brain. Collaborating with experienced neurosurgeons, neuroradiologists and other professionals, our melanoma experts offer a full spectrum of progressive treatment options and trailblazing clinical trials for advanced-stage malignancies.
Medically reviewed by Dr. Peter Forsyth, MD, chairman, Neuro-Oncology Program