Melanoma Removal and Work-up

Last Modified: September 14, 2005

Dear OncoLink "Ask The Experts,"
I recently had a malignant melanoma removed. Is it important to do a wide excision and why? Do I need a sentinel node removal? Can anything else show cancerous cells in my body? Like a PET scan or MRI or CAT scan? Someone told me that every mole in your body could be found to have cancer cells. Is this true? Does the lymph node ever kill the cancer cells?

Suzanne M. McGettigan, MSN, CRNP, AOCN, Board Certified Adult Nurse Practitioner and a Certified Oncology Advanced Practice Nurse, responds:

Malignant melanoma can be found at all different stages. It is best to find melanoma lesions early, since they can possibly be cured with surgery alone at that point.

After having a biopsy that identifies the presence of melanoma, a wide excision is usually performed to remove a rim of normal tissue around the melanoma. This rim of normal tissue is what your healthcare provider will refer to as "margins". Depending on the depth of the melanoma identified during your original biopsy, a sentinel node biopsy may also be performed at this time. This is generally recommended any time the original lesion is greater than 1 millimeter in depth. During a sentinel node biopsy, a dye with a radioactive substance for ease in tracking is injected at the site of the original melanoma lesion and then followed to the lymph node(s) where the melanoma cells would drain. These lymph nodes, as well as the tissue removed during the wide excision, are then examined for the presence of melanoma cells. If the sentinel lymph nodes contain evidence of melanoma, additional lymph nodes may need to be removed.

Depending on the depth of the original melanoma, as well as other characteristics of the original melanoma, (including presence or absence of melanoma in the lymph nodes), further imaging studies may be done. These include a chest X-ray for thin melanomas, and CAT scans or MRI for thicker melanomas. PET scans are often used to further clarify the results of these other scans. A PET scan is best done in conjunction with another scan (CT or MRI) – the two studies "work together" so the doctor can determine if the tumor is located anywhere else in the body.

Almost all moles in your body contain melanin, the pigment that gives them color, but not every mole can become a melanoma. Melanomas often arise in pre-existing moles. This is why it is very important to be aware of any changes that occur in your moles. You should do a self-exam of your skin about once a month, and your health care provider should perform a skin exam with any complete physical exam that you have. This should include all areas of the skin – even the soles of your feet. Characteristics that are associated with the transformation of a mole into melanoma include the ABCDs:

A symmetry meaning that the mole looks different on either side if you drew a line through its center.
B orders that are irregular, rather than even.
C olor variation throughout the mole (red, black, brown, tan).
D iameter great than 6 mm or the size of a pencil eraser (although size should not prevent a mole from being checked if it has any of the other signs).

Lymph nodes are an important part of your immune system. One function of your immune system is to kill any abnormal cells in your body. This includes cancer cells like melanoma. However, these cancerous cells are sometimes able to hide from your immune system. This is what happens in melanoma. Some treatments for melanoma are aimed at revving up your immune system so that it can recognize cancerous cells and destroy them.