What is Melanoma?
Considered the most dangerous form of skin cancer, melanoma develops as a result of unprepared DNA damage to skin cells usually caused by ultraviolet radiation from the sun or tanning beds. Some 180,000 cases of melanoma are estimated to be diagnosed in the United States in 2018.
If detected early, melanoma is a very curable cancer, with an overall five-year survival of 91 percent. If not detected and treated early, it can advance and spread quickly to other parts of the body, where it becomes harder to treat.
- Family or personal history of melanoma
- Fair skin; blonde or red hair
- Three or more blistering sunburns before the age of 20 years
- Presence of actinic keratosis–a rough, scaly patch on the skin from years of sun exposure
- Large number of moles on skin
Most melanomas are pigmented lesions. They may occur in both sun-exposed areas of skin as well as skin that is usually covered, such as toenails and fingernails. Melanomas can also occur in the eye and gastrointestinal tract. Melanoma lesions are more likely to have the following features:
- Larger than six millimeters or recent increase in size
- Asymmetrical in shape
- Bleeding, itching, ulceration, pain
- Different shades of pigmentation within the same lesion
- Indistinct or irregular borders
Melanomas are not necessarily dark in color. Amelanotic melanoma is one in which cancer cells have lost the ability to produce pigment. These non-pigmented lesions can go unnoticed and untreated for a long time.
You should perform monthly total body skin self-examination and have a yearly skin examination by your primary care physician or dermatologist.
Diagnosis and Staging
The diagnosis of melanoma is made by biopsy of the suspicious lesion. The depth or thickness of the melanoma is critical in determining further staging and prognosis.
Once the diagnosis has been made, certain tests are performed to find out how advanced the tumor is. These tests may include:
- Sentinel lymph node biopsy (SLNB)–performed once a melanoma is greater than a certain thickness or has other concerning features
- CT scan
- PET scan
- Blood tests, including lactate dehydrogenase (LDH)
Stages of Melanoma
The stage of a cancer is a standardized description of how far it has spread. The higher the stage, the further it has spread. Importantly, with increasing thickness of the primary tumor, the likelihood of spread to lymph nodes and distant organs increases. Information required to determine the stage of the cancer includes:
- How deeply the melanoma has grown (tumor thickness)
- Whether the melanoma is ulcerated
- Whether the melanoma has spread to nearby lymph nodes and, if so, how many nodes
- Whether the melanoma has spread to other parts of the body (distant metastasis)
Staging describes three elements of a cancer's spread:
- Extent of the primary tumor (T stage)
- Presence and extent of tumor spread to lymph nodes (N stage)
- Presence of spread to other parts of the body (metastasis, M stage)
Stages of melanoma are:
- Stage 1 and 2: No tumor spread to lymph nodes but increasing tumor thickness from stage 1a through to stage 2c
- Stage 3: Tumor present in lymph nodes
- Stage 4: Spread to distant organs (distant metastasis)
Our team of physicians, consisting of surgeons, medical oncologists and radiation oncologists, works together to select the treatment strategy that is best for each individual patient.
- Wide local excision is the primary treatment of most melanomas.
- Sentinel lymph node biopsy (SLNB, discussed above in staging) is usually performed for all tumors thicker than 1mm, and for select lesions 0.75–1.0mm thick. If lymph nodes are found on physical exam or on SLNB, then an operation may be performed to remove all the lymph nodes in that region of the body (in the armpit or in the groin, typically). This operation is called a lymph node dissection.
- Resection of metastases. In select patients, surgery can be performed to remove sites of metastatic disease.
- Isolated limb perfusion or infusion. This therapy is an option for patients with locally advanced, but non-metastatic disease, that cannot be surgically resected. The circulation of the affected limb is isolated from the rest of the body through the use of special catheters, and high dose chemotherapy is infused into the limb.
A drug or combination of drugs is given to kill cancer cells wherever they are in the body. There have been a number of recent clinical trials that have given hope to patients with metastatic melanoma. These trials have used drugs that either stimulate the immune system or target a specific mutation.
Radiation therapy is used infrequently in the treatment of melanoma. It may be used to decrease the risk of tumor recurrence after lymph node dissection.