Melanoma and Merkel Cell Cancer Treatment
There are different types of treatment for patients with these cancers, depending on the stage of the cancer and the person’s overall health. At Siteman, each patient is treated to give the best outcome for their specific cancer, including standard therapies and novel therapies only available in clinical trials. That’s why careful diagnosis is so important. The standard treatments for melanoma and Merkel cell skin cancer include surgery, targeted therapy, immunotherapy, and, less commonly, radiation therapy. Clinical trials are also an option.
Wide local excision
Surgery to remove the tumor is the primary treatment of all stages of melanoma. A wide local excision is used to remove the melanoma and some of the normal tissue around it. The size of the excision is dependent on the thickness of the tumor.
Lymph node sampling, including sentinel biopsy
To test for cancer in lymph nodes, any enlarged lymph nodes that can be felt will be biopsied directly. Otherwise, you may have a sentinel node biopsy, which checks for cancer in the first lymph node the cancer is likely to spread to from the tumor. A radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the dye is removed. A pathologist views the tissue under a microscope to look for cancer cells.
If cancer cells are found, more lymph nodes will be removed and tissue samples checked for signs of cancer. Even if the doctor removes all the melanoma that can be seen at the time of surgery, some patients may be offered systemic therapy or clinical trial enrollment after surgery to kill any cancer cells that may remain.
Isolated limb perfusion (ILI) is a method of drug delivery that is designed to deliver high local doses of chemotherapy for melanomas in the extremities, while avoiding systemic toxicity. ILI involves the following steps: Placement of catheters into a major vein and artery nearest to the tumor, placing a tourniquet around the limb to keep the chemotherapy confined and infusing the drug through the catheters into the affected extremity. Perfusion lasts for approximately 60 minutes and may be done with one or a combination of drugs while the limb is heated to increase the effectiveness of the drugs. Patients are hospitalized until limb inflammation subsides.
Also called biologic therapy, these drugs use the patients’ immune systems to fight the cancer. The following types of biologic therapy are being used or studied in the treatment of melanoma:
- Checkpoint Inhibitor Monoclonal Antibodies: Ipilimumab is a monoclonal antibody that boosts the body’s immune response against melanoma cells. Other monoclonal antibodies are being studied in the treatment of melanoma. Pembrolizumab and Nivolumab can be used to treat patients whose tumor cannot be removed by surgery or has spread to other parts of the body. This immune-based cancer treatment, which has been successful against advanced skin cancers in clinical trials, takes advantage of immune T cells that are present in many tumors. These T cells have been shut off by cancer cells activating a safety mechanism called the checkpoint system, which prevents immune cells from attacking the body’s own tissues.
Checkpoint blockade drugs in testing disable that safety mechanism, allowing our immune T cells to use their destructive capabilities on the tumors. Researchers have found that by identifying mutated tumor proteins that are the specific targets of the reactivated T cells that attack the tumors, they can create vaccines that only unleash the T cells on the tumors, rather than on healthy tissue.
- Interferon affects the division of cancer cells and can slow tumor growth.
- Interleukin-2 (IL-2) boosts the growth and activity of many immune cells, especially lymphocytes so they can attack and kill cancer cells.
This type of treatment uses drugs or other substances to attack cancer cells, usually causing less harm to normal cells than chemotherapy or radiation therapy. The following types of targeted therapy are used or are being studied in the treatment of melanoma:
- Signal transduction inhibitor therapy blocks signals that are passed from one molecule to another inside a cell to kill cancer cells. Several different types are used to treat some patients with advanced melanoma or tumors that cannot be removed by surgery. If your melanoma has a certain mutation, you may receive a BRAF or MEK inhibitor therapy.
- Oncolytic virus therapy is a type of targeted therapy that is being studied in the treatment of melanoma that uses a virus that infects and breaks down cancer cells but not normal cells. Radiation therapy or chemotherapy may be given after oncolytic virus therapy to kill more cancer cells.
- Angiogenesis inhibitors are a type of investigational targeted therapy that blocks the growth of new blood vessels. In cancer treatment, they may be given to prevent the growth of new blood vessels that tumors need to grow.
For melanoma, systemic chemotherapy is used less frequently than it was five to 10 years ago because of the increasing use of targeted and immunotherapies. In general, chemotherapy drugs provide low response rates (5 to 10 percent) and have failed to prolong survival in patients with metastatic melanoma.
Radiation may be selectively used in the treatment of melanoma for very specific indications.
Standard Treatments for Merkel Cell Skin Cancer
For Merkel cell, surgical excision, sometimes sentinel lymph node biopsy for certain size tumors, radiation therapy and clinical trials may be suggested. Other types of treatments are being studied in clinical trials.