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Melanoma and Other Skin Cancers

  • Posted: 01/11/2011

Staging

If the biopsy shows that you have skin cancer, your doctor needs to learn the stage (extent) of the disease to help you choose the best treatment.

The stage is based on:

  • The size (width) of the growth
  • How deeply it has grown beneath the top layer of skin
  • Whether cancer cells have spread to nearby lymph nodes or to other parts of the body

When skin cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary (original) tumor. For example, if skin cancer spreads to the lung, the cancer cells in the lung are actually skin cancer cells. The disease is metastatic skin cancer, not lung cancer. For that reason, it's treated as skin cancer, not as lung cancer. Doctors sometimes call the new tumor "distant" disease.

Blood tests and an imaging test such as a chest x-ray, a CT scan, an MRI, or a PET scan may be used to check for the spread of skin cancer. For example, if a melanoma growth is thick, your doctor may order blood tests and an imaging test.

For squamous cell skin cancer or melanoma, the doctor will also check the lymph nodes near the cancer on the skin. If one or more lymph nodes near the skin cancer are enlarged (or if the lymph node looks enlarged on an imaging test), your doctor may use a thin needle to remove a sample of cells from the lymph node (fine-needle aspiration biopsy). A pathologist will check the sample for cancer cells.

Even if the nearby lymph nodes are not enlarged, the nodes may contain cancer cells. The stage is sometimes not known until after surgery to remove the growth and one or more nearby lymph nodes. For thick melanoma, surgeons may use a method called sentinel lymph node biopsy to remove the lymph node most likely to have cancer cells. Cancer cells may appear first in the sentinel node before spreading to other lymph nodes and other places in the body.

Stages of Melanoma

These are the stages of melanoma:

  • Stage 0: The melanoma involves only the top layer of skin. It is called melanoma in situ.
  • Stage I: The tumor is no more than 1 millimeter thick (about the width of the tip of a sharpened pencil.) The surface may appear broken down. Or, the tumor is between 1 and 2 millimeters thick, and the surface is not broken down.
  • Stage II: The tumor is between 1 and 2 millimeters thick, and the surface appears broken down. Or, the thickness of the tumor is more than 2 millimeters, and the surface may appear broken down.
  • Stage III: The melanoma cells have spread to at least one nearby lymph node. Or, the melanoma cells have spread from the original tumor to tissues nearby.
  • Stage IV: Cancer cells have spread to the lung or other organs, skin areas, or lymph nodes far away from the original growth. Melanoma commonly spreads to other parts of the skin, tissue under the skin, lymph nodes, and lungs. It can also spread to the liver, brain, bones, and other organs.

Stages of Other Skin Cancers

These are the stages of basal cell and squamous cell skin cancers:

  • Stage 0: The cancer involves only the top layer of skin. It is called carcinoma in situ.

    Bowen disease is an early form of squamous cell skin cancer. It usually looks like a reddish, scaly or thickened patch on the skin. If not treated, the cancer may grow deeper into the skin.
  • Stage I: The growth is as large as 2 centimeters wide (more than three-quarters of an inch or about the size of a peanut).
  • Stage II: The growth is larger than 2 centimeters wide.
  • Stage III: The cancer has invaded below the skin to cartilage, muscle, or bone. Or, cancer cells have spread to nearby lymph nodes. Cancer cells have not spread to other places in the body.
  • Stage IV: The cancer has spread to other places in the body. Basal cell cancer rarely spreads to other parts of the body, but squamous cell cancer sometimes spreads to lymph nodes and other organs.


Glossary Terms

Bowen disease (BOH-en dih-ZEEZ)
A skin disease marked by scaly or thickened patches on the skin and often caused by prolonged exposure to arsenic. The patches often occur on sun-exposed areas of the skin and in older white men. These patches may become malignant (cancer). Also called precancerous dermatitis and precancerous dermatosis.
carcinoma in situ (KAR-sih-NOH-muh in SY-too)
A group of abnormal cells that remain in the place where they first formed. They have not spread. These abnormal cells may become cancer and spread into nearby normal tissue. Also called stage 0 disease.
cartilage (KAR-tih-lij)
A tough, flexible tissue that lines joints and gives structure to the nose, ears, larynx, and other parts of the body.
chest x-ray (chest EX-ray)
An x-ray of the structures inside the chest. An x-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.
CT scan (… skan)
A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.
fine-needle aspiration biopsy (... NEE-dul AS-pih-RAY-shun BY-op-see)
The removal of tissue or fluid with a thin needle for examination under a microscope. Also called FNA biopsy.
melanoma in situ (MEH-luh-NOH-muh in SY-too)
Abnormal melanocytes (cells that make melanin, the pigment that gives skin its color) are found in the epidermis (outer layer of the skin). These abnormal melanocytes may become cancer and spread into nearby normal tissue. Also called stage 0 melanoma.
metastatic (meh-tuh-STA-tik)
Having to do with metastasis, which is the spread of cancer from the primary site (place where it started) to other places in the body.
MRI
A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.
PET scan (… skan)
A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called positron emission tomography scan.
sentinel lymph node biopsy (SEN-tih-nel limf node BY-op-see)
Removal and examination of the sentinel node(s) (the first lymph node(s) to which cancer cells are likely to spread from a primary tumor). To identify the sentinel lymph node(s), the surgeon injects a radioactive substance, blue dye, or both near the tumor. The surgeon then uses a probe to find the sentinel lymph node(s) containing the radioactive substance or looks for the lymph node(s) stained with dye. The surgeon then removes the sentinel node(s) to check for the presence of cancer cells.
surgeon (SER-jun)
A doctor who removes or repairs a part of the body by operating on the patient.
surgery (SER-juh-ree)
A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.