When doctors diagnose melanoma, they also assign it a stage. The stage refers to the size and spread of the melanoma. Knowing the stage of your skin cancer helps your doctor create your treatment plan. This article will cover the stages of melanoma and what they tell your oncologist (cancer specialist) about your tumor.

TNM Staging for Melanoma

After your doctor takes a tissue sample of your melanoma, they’ll send it to a lab for analysis. Known as a biopsy, this procedure helps determine your stage of melanoma.

The American Joint Committee on Cancer (AJCC) developed a staging system that uses the acronym TNM (tumor, lymph nodes, metastasis). This information is then used to assign a number stage.

T — Tumor

The “T” in TNM stands for “tumor,” which takes into account how deep the tumor is within the skin and whether it has ulcerated. Melanoma tumor thickness is called the Breslow measurement.

Doctors measure thickness to determine the tumor’s chances of spreading. A tumor less than 1 millimeter thick isn’t likely to spread. For reference, that’s about the thickness of a penny, and a nickel is around 2 millimeters thick.

Ulceration refers to the breakdown of the skin covering the melanoma. The American Cancer Society notes that ulceration is associated with a poor outlook (prognosis).

N — Lymph Nodes

“N” stands for “lymph nodes.” Oncologists check to see how many lymph nodes, if any, are affected by melanoma. Lymph nodes are tiny structures that filter fluid running through your lymphatic system. This system carries your immune cells throughout your body to look for cancer and invading viruses or bacteria. Many types of cancer spread into nearby lymph nodes, which can lead to new tumors in other areas of the body.

M — Metastasis

“M” stands for “metastasis,” or the spread of cancer to distant parts of the body. Melanoma most commonly spreads to skin or lymph nodes or to the bones, brain, lungs, liver, or intestines.

Staging Your Melanoma

The TNM system assigns a number after the letter to tell you more about your melanoma. The bigger the number, the more severe the tumor is. For example, a T2 tumor is larger or has spread more than a T1 tumor.

Once your oncologist has collected all the needed information, they’ll diagnose you with a specific stage of melanoma. Melanoma stages range from 0 to 4, sometimes written in Roman numerals (I, II, III, and IV). Stages are divided further using capital letters, like A, B, and C. For example, stage 3A cancer is a lower stage than 3B.

Clinical vs. Pathological Staging

Two types of staging, clinical and pathological, are used to diagnose melanoma. Clinical stage is based on the results of biopsies and imaging tests. Your clinical stage is useful for planning treatment, but it may not provide enough information to give an accurate picture of your melanoma.

After surgically removing the tumor and nearby skin and lymph nodes, your oncologist can determine your pathological stage. Your pathological stage is best for predicting your outlook with melanoma.

Stage 0 Melanoma

Stage 0 melanoma is also referred to as melanoma in situ — melanoma that’s “in place.” You’ll be diagnosed with stage 0 melanoma if cancer cells are found only in the top layer of skin (the epidermis). Melanoma in situ is very unlikely to spread to nearby lymph nodes or other parts of the body.

Stage 1 Melanoma

Stage 1 melanoma has spread into the middle layer of skin (the dermis). Oncologists divide stage 1 into two subgroups, 1A and 1B. The subgroups take into consideration the tumor thickness and whether there’s ulceration.

The primary or original tumor is no more than 2 millimeters thick in stage 1. At this point, the melanoma hasn’t spread to nearby lymph nodes or distant parts of the body.

Stage 2 Melanoma

Stage 2 melanoma is thicker than stage 1 and is found deeper within the skin layers. Oncologists divide stage 2 into three subgroups — 2A, 2B, and 2C.

The primary tumor may be thicker than 1 millimeter — even thicker than 4 millimeters — and may or may not have ulceration. At this point, the melanoma still hasn’t spread into nearby lymph nodes. However, it’s now deeper in the skin and closer to lymph nodes, so it’s more likely to spread.

Your oncologist may recommend a sentinel lymph node biopsy to make sure your melanoma hasn’t spread. During this procedure, your oncologist will use a radioactive substance to mark nearby lymph nodes. A surgeon will remove the lymph nodes to check for melanoma cells.

Sentinel lymph nodes are those closest to the tumor. If there are melanoma cells in a sentinel lymph node, your oncologist will check other lymph nodes and potentially restage your cancer.

Stage 3 Melanoma

In stage 3 melanoma, the primary tumor has spread to the lymph nodes. The tumor may have also spread into small areas of surrounding skin. This is known as a satellite tumor or in-transit metastasis. Stage 3 melanoma is divided into four subgroups — A, B, C, and D.

When diagnosing stage 3 melanoma, oncologists consider several factors:

• How thick your primary tumor is
• Whether there’s any ulceration
• How many lymph nodes the melanoma has spread to
• If any in-transit metastases are next to the primary tumor

Stage 4 Melanoma

Stage 4 melanoma — also known as metastatic melanoma — has spread to distant parts of the body. Melanoma is most likely to spread to the skin and lymph nodes first.

Oncologists don’t use subgroups for stage 4 melanoma. However, the “M” (for metastasis) can vary depending on where in the body the cancer has spread. Your oncologist will also measure the level of lactate dehydrogenase (LDH) in your blood. LDH is a marker that lets your oncologist know how aggressive your cancer is.

If you’re diagnosed with stage 4 melanoma, you may see the following on your report:

• M1a — Metastasis to distant skin, lymph nodes, or soft tissue (muscle)
• M1b — Metastasis to the lungs
• M1c — Metastasis to an internal organ like the liver or bones
• M1d — Metastasis to the central nervous system, like the brain and spinal cord

What Your Melanoma Stage Means Moving Forward

After your oncologist determines your melanoma stage, they’ll create your treatment plan. Early-stage melanomas are mostly treated with surgery since the tumors haven’t spread. Later-stage melanomas (some stage 2, as well as stages 3 and 4) may require surgery to remove the tumor, and additional medications may be used to kill any melanoma cells left behind. Talk to your oncologist if you’re interested in learning more about your melanoma stage and treatment plan.

What Happens if Your Melanoma Returns?

After you’ve completed your treatment plan and have no signs of melanoma, you enter remission. Your oncologist will monitor you regularly to make sure your melanoma doesn’t return (recur). Your melanoma stage can affect how likely it is that your cancer will come back. The higher the stage, the higher the chance of recurrence.

If your melanoma returns, your oncologist will have to restage your cancer. They’ll run similar tests to figure out how far your melanoma has spread and what new treatments you’ll need.

Talk With Others Who Understand

MyMelanomaTeam is the social network for people with melanoma and their loved ones. On MyMelanomaTeam, members come together to ask questions, give advice, and share their stories with others who understand life with melanoma.

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