Overview

Malignant melanoma is a serious type of skin cancer that can affect the legs and feet, as well as other parts of the body. In this disease, pigment-producing cells (melanocytes) become cancerous and grow and divide at an uncontrolled rate. The primary risk factor for malignant melanoma is exposure to ultraviolet radiation (UV rays); the mechanism by which UV rays cause melanoma is unknown.

Melanoma is less common than other types of skin cancer (e.g., basal cell carcinoma, squamous cell carcinoma), but it is more likely to spread (metastasize) via cells that break away from the original tumor, travel through the blood or lymphatic vessels, and grow within other parts of the body.

Treatment

Treatment options for skin cancer include surgery, cryosurgery (i.e., application of extreme cold to destroy cancerous tissue), radiation, and electrodessication (i.e., destroying tissue using electrical current and removing the tissue using curettage). Other treatments, such as chemotherapy, immunotherapy, and vaccine therapy may be used in some cases.

Surgery

In about 95% of cases, melanoma treatment involves surgical removal (resection) of the lesion and an area of surrounding tissue. Satellite tumors often develop separately close to the primary tumor.

Melanomas less than 1 mm thick (i.e., thin tumors), usually require a surgical margin of 1 cm. This means that 1 cm of surrounding tissue is removed on all sides of the primary tumor. Melanomas between 1 and 4 mm (i.e., intermediate thickness) require a surgical margin of 2 cm. There is no clear standard for an adequate margin in melanomas thicker than 4 mm (i.e., thick melanomas).

Other standards are applied for parts of the body where it is not possible to remove so much tissue. These standards are as follows:

• Melanomas that occur on the skin or under the nails of the fingers or toes may require amputation of the digit, saving as much of the finger or toe as possible.
• For small melanomas on the ears, a wedge-shaped biopsy is done to remove the cancerous tissue. For larger melanomas, part of the ear may need to be amputated.
• There are no set standards for melanomas on the face. Surgeons must use their best judgment based on the location, width, and depth of the lesion.
• There are no set standards for melanomas on the bottom (sole) of the foot. Surgeons take into account the location, width, and depth of the lesion.

Lymph Node Dissection

If the melanoma has metastasized to the nearby lymph nodes (the regional lymph nodes), there are several options. Twenty-five to 50% of all patients with regional lymph node metastasis can be cured with surgical removal of the lymph nodes. The surgery is called a therapeutic or delayed lymph node dissection (TLND) and involves removing only those lymph nodes that feel hard or enlarged or show other clinical symptoms of having melanoma in them.

If all of the lymph nodes in an area are removed, whether or not they show any clinical symptoms of having cancerous cells in them, the surgery is called an elective lymph node dissection (ELND). ELNDs are a highly controversial practice; if recommended by a surgeon, a second opinion should be obtained. As much information as possible should be gathered about treatment options. ELNDs are usually most appropriate for people with in-transit metastases.

In-transit metastases are cancerous cells that are found between the primary tumor in the skin and the closest lymph node. They result from a melanoma cell somehow becoming trapped in one of the lymphatic channels.

Adjuvant Therapies for Later Stage Melanoma

An adjuvant therapy is one that is used in addition to the primary therapy, which in the case of melanoma is surgery (surgical removal of the tumor as well as the lymph nodes, if necessary). The advantages of chemotherapy and/or immunotherapy in addition to surgery are not proven. Many clinical trials are currently underway to test new drugs and products that may aid in the treatment of stage IIB, and especially stage III melanoma.

Chemotherapy

Chemotherapy is used as an adjuvant therapy, following surgery, for patients with stage IIB and III melanomas. Sometimes the drugs are injected into the arm or leg (isolated limb perfusion), so that the patient receives the drugs only in the part of the body that is affected by the cancer, thereby decreasing the number of normal cells that are killed by the anti-cancer drugs along with all the cancer cells. Isolated limb perfusion is the treatment of choice for patients with in-transit metastasis. Often chemotherapy is combined with immunotherapy.

Immunotherapy

Immunotherapy is the use of naturally occurring or synthetically made biological products that can boost a person’s immune system to fight off cancer. Along with chemotherapy, immunotherapy is considered an adjuvant therapy for patients with more advanced stages of melanoma. Cytokine therapy, for example, is the use of proteins called cytokines that activate the immune system and can shrink 10-20% of all metastatic tumors in patients with stage III or IV melanomas. Immunotherapy with interferon is sometimes used for stage III melanoma; there are severe side effects associated with interferon.

Researchers are studying many different types of products that could be used in immunotherapy, including a possible vaccine that could be injected to stimulate an immune response to melanoma. Those interested in learning more about clinical trials (the study of an experimental treatment) in progress should consult their physician and check with the National Cancer Institute.

Radiation Therapy

The primary use of radiation therapy for melanoma patients is as a palliative treatment (it treats the symptoms but not the actual cancer) for stage IV disease. Sometimes, for example, if melanoma has metastasized to the brain and is causing dizziness, paralysis, or other symptoms, radiation therapy can provide some relief from these symptoms.

Radiation therapy is sometimes used as an adjuvant therapy for stage III patients. It may be used in addition to the therapeutic lymph node dissection (TLND), often as an alternative to an ELND.

Treatment by Stage

Recurrent Melanoma

When melanoma recurs, there are several treatment options, depending on the stage of the original melanoma, the initial treatment, and how extensive the recurrence is. If the recurrence is a local skin tumor, then it is surgically removed. If it involves the lymph nodes, then the recurrence is treated with a therapeutic lymph node dissection, which involves removing only those lymph nodes that show evidence of melanoma.

A patient might want to consider participating in a chemotherapy or combined chemo-immunotherapy clinical trial. If the cancer has spread to other parts of the body, it is treated as any stage IV melanoma would be treated.

Patients with stage III melanoma have the highest risk of recurrence. The relapse rate of these patients may be as high as 50% (that is, 50% of all patients with stage III melanoma will have it again, even after they’ve been successfully treated).

Prevention

The best way to prevent skin cancer is to avoid sunbathing and tanning salons. Sunscreen should be used before any prolonged exposure to the sun. All skin lesions should be checked and if changes are detected in a mole or skin lesion, or if one is even mildly suspicious about the appearance of one, a doctor should be consulted promptly.

Source: podiatrychannel.com