Malignant melanoms of the left side. Photo courtesy Dr. SG Green
The treatment of melanoma skin cancer, no matter the stage, involves the surgical removal of the cancer and a margin of normal skin around the tumor. For stage III and IV cancers additional treatments may be necessary.
Surgical treatment: The amount of normal skin removed around the cancer is determined by the Breslow's thickness of the tumor. The wide margins are necessary because melanoma cells frequently travel to nearby skin, often within a 1 inch distance from the cancer. The thicker the cancer, the further away cells may have traveled. The standard recommendations are:
1) For in situ melanoma: the excision should remove 0.5 cm (about 1/3 inch) of normal skin outside of the tumor edges.
2) Melanomas which are 1.0 mm in thickness need 1.0 cm (just under 1/2 inch) of clear margin.
3) If the melanoma is 2.0 mm or greater in thickness then a 2-3 cm (about 1 inch) margin is needed.
Note: The clear margin must be all the way around the tumor, so a 1 cm diameter cancer will need an excision that is 3 cm in width. A simple excision requires a length 3 times longer than the width to close smoothly, so the 1 cm example cited will have an incision 9 cm long (about 4 inches). When the tumor is in an area, such as the face, where important structures could be damaged by this simple excision and closure, skin grafts or rotation flaps may be performed. A skin graft is a piece of skin which is cut out of an area of the body which will not show, such as behind the ear, and stitched into place in the surgical wound. A flap is taken from next to the surgery site as a peninsula-shaped piece of skin and rotated into the surgery site and stitched into place.
Lymph nodes: The lymph nodes which drain from the tumor are an important consideration during surgery. If any of the nodes can be felt through the skin they will be removed, usually at the time the cancer is removed. If there are not any nodes which can be felt, the treating physician may opt to just watch the lymph nodes if the cancer is very thin. A commonly used test now is the "sentinal node biopsy," which will identify the lymph node nearest to the tumor and thus the one most likely to have cancer in it.
Adjuvant treatment: Additional (also called adjuvant) treatment is usually needed for patients with later stage (stage III and stage IV) cancers. By definition, these tumors have spread from the original site of the tumor into the nearby or distant lymph nodes, or skin (stage III) or into other organs (stage IV). As with earlier stages of disease, surgical removal of the known tumor is the first step in treatment. Next, the patient may need:
Chemotherapy: Tests are being conducted on a number of chemotherapy agents (drugs which kill cancer cells), but the only medication which is approved by the Food and Drug Administration (FDA) is Darcarbazine (also called DTIC). This drug may be used in combination with other chemotherapy agents such as: vinblastine, cisplatin, tamoxifen, or carmustin (also called BCNU). The response of melanoma to any or all of these medications has been very limited.
In recent years a new type of drug has been developed for cancer that prevents the growth of blood vessels necessary to feed the tumor (anti-angiogenesis drugs). These medications are still in the experimental stage, but include: thalidomide, angiostatin and endostatin.
Immunotherapy: The medications in this class of drugs attempt to activate the immune system to attack the tumor. The ultimate goal for the current studies is to develop a "vaccine" to immunize patients who have melanoma against their own tumor. This idea is based on the observation that some patients' immune systems may completely destroy a melanoma, and there are many cases where immune cells are attacking the deeper cells of a tumor. These treatments are investigational at this time but some patients with late stage cancers may be able to join a study and be treated with these agents.
Another type of immunotherapy, more commonly called biologic therapy, uses chemicals that the body makes naturally. The most familiar one is interferon alpha, which is approved by the FDA and which has been shown to increase the five-year survival rate of Stage III patients. Another chemical being tested is tumor necrosis factor (TNF). Both substances are produced by white blood cells and also have some anti-angiogenesis properties. Both interferon alpha and TNF have significant side effects.
The final type of immunotherapy is with lymphokines, which are also natural products of the body, Lymphokines are produced by white blood cells which have been stimulated by contact with certain substances. The lymphokines make the cells better able to kill malignant cells. The best known lymphokine is interleukin 2, which is being studied with and without interferon alpha as a treatment for melanoma. These studies are early and experimental and interleukin 2, like interferon alpha and TNF, is associated with significant side effects when used in cancer killing doses.
Gene therapy: This type of treatment is in the very early experimental stage for treatment of a number of medical problems, including melanoma. The idea is to identify the genes which make proteins which are produced by the melanoma and not the normal cells of the body. These are all proteins which sit on the outside of the melanoma cells and can be identified by immune cells. If the cells can be induced to produce more of these proteins then the body can mount a more effective attack on the tumor cells.
Follow-up: In the treatment of melanoma it is extremely important that patients follow-up with their doctors as scheduled. Melanoma is a cancer that can be invisible inside the body for 15-20 years after the skin lesion is removed and then reappear as widespread metastases in multiple organs. Patients who have had one melanoma are also at increased risk of developing other, completely new, melanomas. First degree relatives of a melanoma patient have an increased risk of developing melanoma, as well and should be screened by a dermatologist for abnormal moles at least once a year. A first degree relative of a patient is their parents, siblings, and children.
For more info: see the Skin Cancer Foundation and American Cancer Society websites. The American Cancer Society site has a personalized tool which patients can use to find out about the potential treatments for their cancer. This service requires confidential registration and information about the patient's cancer type and stage, but all services are free.
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