Melanoma is a type of skin cancer that results when cancerous cells start to grow in melanocytes, or cells that produce melanin. These are the cells responsible for giving the skin its color. Melanoma can occur anywhere on the skin, even in the eyes. Although the condition is rare, doctors are diagnosing a larger number of people with melanoma than ever before.
If a person has been diagnosed with melanoma, a doctor will conduct tests to determine how much the melanoma has spread and how large the tumor is. A doctor will then use this information to assign a stage to the cancer type. There are five main stages of melanoma, from stage 0 to stage 4. The higher the number, the more advanced the cancer tends to be.
By using the staging process, doctors and patients are better able to understand their treatment options and prognosis. Staging provides a quick reference point to help doctors communicate with one another regarding a person’s treatment plan and overall outlook.
Doctors will recommend a number of testing methods to determine the existence and spread of the melanoma. Examples of these methods include:
- Physical exam. Melanoma can grow anywhere on the body. This is why doctors often recommend thorough skin checks, including on the scalp and in between the toes. A doctor may also ask about any recent changes in the skin or in existing moles.
- CT scan. Also called a CAT scan, a CT scan can create images of the body to identify potential signs of tumor and tumor spread.
- Magnetic resonance imaging (MRI) scan. This scan uses magnetic energy and radio waves to generate images. A doctor can administer a radioactive material known as gadolinium that highlights cancer cells.
- Positron emission tomography (PET) scan. This is another imaging study type that tests for where the body is using glucose (blood sugar) for energy. Because tumors consume glucose more significantly, they will often show up as bright spots on the imaging.
- Blood testing. People with melanoma may have higher-than-normal levels of the enzyme lactate dehydrogenase (LDH).
- Biopsy. A doctor may take a sample of a potentially cancerous lesion as well as nearby lymph nodes.
Doctors will consider the results of each of these tests when determining cancer stage.
Doctors most commonly use a staging system known as the American Joint Committee on Cancer (AJCC) TNM system. Each letter of the TNM system plays a role in staging the tumor.
- T is for tumor. The larger a tumor has grown, the more advanced the tumor tends to be. Doctors will assign a T-score based on the size of the melanoma. A T0 is no evidence of a primary tumor, while a T1 is a melanoma that is 1.0 millimeter thick or less. A T4 melanoma is greater than 4.0 millimeters.
- N is for lymph nodes. If a cancer has spread to the lymph nodes, it is more serious. An NX is when a doctor cannot assess the regional nodes, while an N0 is when a doctor cannot detect the cancer has spread to other nodes. An N3 assignment is when the cancer has spread to many lymph nodes.
- M is for metastasized. If the cancer has spread to other organs, the prognosis is usually poorer. An M0 designation is when there is no evidence of metastases. An M1A is when the cancer has metastasized to the lung. However, an M1C is when the cancer has spread to other organs.
Doctors will use the “score” from each of these factors to determine a melanoma stage.
Stages and treatment
The following table describes each melanoma stage and the typical treatments for each. However, these can vary based on someone’s overall health, age, and their personal wishes for treatments.
|0||The tumor has only penetrated the epidermis, or outermost skin layer. Another name for this is melanoma in situ.||A doctor will usually remove the tumor and some cells around the tumor to ensure the cancer is fully removed. Routine follow-up visits and skin checks are recommended.|
|1A||The tumor is no more than 1 millimeter thick and hasn’t spread to lymph nodes or organs. The skin doesn’t appear scraped or cracked at the melanoma site.||The tumor is surgically removed. Routine skin examinations should continue, but further treatment is not usually needed.|
|1B||The tumor meets one of two criteria. First, it is less than 1 millimeter thick and has a cracked skin appearance, or second, it is 1 to 2 millimeters thick without a cracked appearance. It hasn’t spread to other lymph nodes or organs.||Surgical removal of the tumor and surrounding cells is usually all that is required. Frequent monitoring for new and concerning skin growths is also recommended.|
|2A||The tumor is 1 to 2 millimeters thick and has a cracked appearance or is 2 to 4 millimeters thick and cracked. The tumor hasn’t spread to lymph nodes or surrounding organs.||Surgical removal of the tissue and surrounding organs as well as potential additional treatments, such as chemotherapy and radiation, may be recommended.|
|2B||The tumor is 2 to 4 millimeters thick and cracked or more than 4 millimeters thick and not cracked in appearance. The tumor hasn’t spread to other organs.||Surgical removal of the tumor and some surrounding tissues may be required. Treatments may also include chemotherapy and radiation as needed.|
|2C||The tumor is more than 4 millimeters thick and is cracked in appearance. These tumors are more likely to spread quickly.||A doctor will surgically remove the tumor. Additional treatments may include chemotherapy and/or radiation.|
|3A3B, 3C||The tumor can be of any thickness. However, the cancerous cells have spread to lymph nodes or to some tissue that is just outside the tumor.||Surgical removal of the lymph nodes is recommended. Additional treatments may include the immunotherapies Yervoy or Imylgic. These are FDA-approved treatments for stage 3 melanoma.|
|4||The cancerous cells have spread or metastasized far beyond the original tumor. They may be in the lymph nodes, other organs, or distant tissues.||Surgical removal of the tumor and lymph nodes are recommended. Additional treatments may include immunotherapy medications, targeted melanoma treatments, or participation in clinical trials.|
As mentioned earlier, melanoma is a rare form of skin cancer. Sometimes a person may not have a significant history of sun exposure yet still get melanoma. This could be due to a family history of the condition. However, there are some steps you can take to reduce your risk for melanoma:
- Avoid excess sun exposure and stay in the shade whenever possible to avoid the sun’s rays.
- Refrain from using tanning beds or sunlamps in an attempt to tan. According to the American Cancer Society, those who use tanning beds are at increased risk for melanoma.
- Use the mnemonic device “Slip! Slop! Slap … and Wrap!” to remember to slip on a shirt, slop on sunscreen, slap on a hat, and wrap on sunglasses to protect your eyes against the sun’s rays.
- Conduct regular skin checks to look for signs of changing moles. Some people may take pictures of their skin and compare them on a monthly basis to determine if any changes have taken place.
Any time a person observes a changing mole or an area of skin that appears crusted, cracked, or otherwise ulcerated in appearance should seek a dermatologist to evaluate for a possibly cancerous lesion.