Diagnosis of Melanoma
The doctor will ask about your symptoms and medical history and perform a physical exam. Many cases of melanoma are found during routine physical exams or when doing a skin self-exam.
Skin Exam and Mole Biopsy
The doctor will examine your skin and moles. If any of your moles look like they may be cancerous, the doctor will take a biopsy (tissue sample) and send it to a laboratory for testing. A pathologist will examine the tissue sample under a microscope to check for cancer cells. Other moles will be monitored over time.
Lymph Node Exam and Biopsy
The doctor may also examine lymph nodes in the groin, underarm, neck, or areas near the suspicious mole. Enlarged lymph nodes suggest that the melanoma may have spread beyond the mole. The doctor may need to remove a sample of lymph node tissue (a biopsy) to test for cancer cells. It is important to know whether the melanoma has extended beyond the tumor site to involve lymph nodes as this changes both the stage of the tumor and the treatment required.
Once melanoma is found, tests are performed to find out the thickness of the primary lesion and whether the cancer has spread and, if so, to what extent. This information helps your doctor to determine which treatment is best for you. Melanoma, like other cancers, is classified according to stages. The lower the stage, the more likely the tumor is to be cured and the easier it is to treat.
Staging is a careful attempt to determine the extent of the cancer invasion. It considers the thickness of the tumor, presence of cancer cells in local lymph nodes, whether the cancer has spread beyond its primary localization and, if it has, what body parts are affected. Depending on the thickness of the original tumor, additional tests to determine staging may include:
- Urine and blood tests
- Chest x-rays
- Bone, liver, or brain scans—These tests look for evidence of tumors in these areas. A radioactive substance is injected into your bloodstream and tracked by a scanning machine. Cancerous areas absorb more of the radioactive substance than normal tissue and show up as “hot spots.”
- PET scan—A radioactive substance is injected into your bloodstream and tracked by a scanning machine. Cancerous areas absorb more of the radioactive substance than normal tissue and show up as “hot spots.”
- Sentinel lymph node study—Here the surgeon injects a radioactive tracer into the tumor site and then follows the tracer into the lymph node region. They then selectively remove only those nodes that pick up the radioactivity to see if they have cancer in them. If they do, a more complete lymph node dissection is performed, as is chemotherapy and immunotherapy. If none of the lymph nodes have cancer in them, the procedure is completed and further therapies are usually not offered unless the tumor itself was quite deep or large.
The following stages are currently used to classify melanoma:
Stage 0 (Melanoma in Situ)
In stage 0, abnormal melanocytes are found in the epidermis (outer layer of the skin). These abnormal melanocytes may become cancer and spread into nearby normal tissue. Stage 0 is also called melanoma in situ.
In stage I, cancer has formed. Stage I is divided into stages IA and IB.
- Stage IA: In stage IA, the tumor is not more than 1 millimeter thick, with no ulceration. The tumor is in the epidermis and upper layer of the dermis.
- Stage IB: In stage IB, the tumor is either not more than 1 millimeter thick, with ulceration, and may have spread into the dermis or the tissues below the skin; or 1 to 2 millimeters thick, with no ulceration.
Stage II is divided into stages IIA, IIB, and IIC.
Stage IIA: In stage IIA, the tumor is either:
- 1 to 2 millimeters thick, with ulceration
- 2 to 4 millimeters thick, with no ulceration
Stage IIB: In stage IIB, the tumor is either:
- 2 to 4 millimeters thick, with ulceration
- More than 4 millimeters thick, with no ulceration
- Stage IIC: In stage IIC, the tumor is more than 4 millimeters thick, with ulceration.
In stage III, the tumor may be any thickness, with or without ulceration, and:
- Has spread to 1 or more lymph nodes; or
- Has spread into the nearby lymph system but not into nearby lymph nodes; or
- Has spread to lymph nodes that are matted (not moveable); or
- Satellite tumors (additional tumor growths within 2 centimeters of the original tumor) are present and nearby lymph nodes are involved.
In stage IV, the tumor may be any thickness, with or without ulceration, may have spread to 1 or more nearby lymph nodes, and has spread to other places in the body.
American Cancer Society website. Available at: http://www.cancer.org/docroot/home/index.asp .
National Cancer Institute website. Available at: http://www.cancer.gov/ .
Last reviewed July 2008 by
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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