Merkel Cell Carcinoma Treatment Option Overview

There are different types of treatment for patients with Merkel cell carcinoma.

Different types of treatments are available for patients with Merkel cell carcinoma. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Four types of standard treatment are used:

Surgery

One or more of the following surgical procedures may be used to treat Merkel cell carcinoma:

• Wide local excision: The cancer is cut from the skin along with some of the tissue around it. A sentinel lymph node biopsy may be done during the wide local excision procedure. If there is cancer in the lymph nodes, a lymph node dissection also may be done.
• Lymph node dissection: A surgical procedure in which the lymph nodes are removed and a sample of tissue is checked under a microscope for signs of cancer. For a regional lymph node dissection, some of the lymph nodes in the tumor area are removed; for a radical lymph node dissection, most or all of the lymph nodes in the tumor area are removed. This procedure is also called lymphadenectomy.

After the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer. It is used to treat Merkel cell carcinoma, and may also be used as palliative therapy to relieve symptoms and improve quality of life.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy).

Immunotherapy

Immunotherapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This cancer treatment is a type of biologic therapy.

Some types of immune cells, such as T cells, and some cancer cells have certain proteins, called checkpoint proteins, on their surface that keep immune responses in check. When cancer cells have large amounts of these proteins, they will not be attacked and killed by T cells. Immune checkpoint inhibitors block these proteins and the ability of T cells to kill cancer cells is increased.

There are two types of immune checkpoint inhibitor therapy:

• PD-1 and PD-L1 inhibitor therapy: PD-1 is a protein on the surface of T cells that helps keep the body's immune responses in check. PD-L1 is a protein found on some types of cancer cells. When PD-1 attaches to PD-L1, it stops the T cell from killing the cancer cell. PD-1 and PD-L1 inhibitors keep PD-1 and PD-L1 proteins from attaching to each other. This allows the T cells to kill cancer cells. Pembrolizumab (a type of PD-1 inhibitor) and avelumab (a type of PD-L1 inhibitor) are used to treat advanced Merkel cell carcinoma. Nivolumab is a type of PD-1 inhibitor being studied to treat advanced Merkel cell carcinoma.

• CTLA-4 inhibitor therapy: CTLA-4 is a protein on the surface of T cells that helps keep the body’s immune responses in check. When CTLA-4 attaches to another protein called B7 on a cancer cell, it stops the T cell from killing the cancer cell. CTLA-4 inhibitors attach to CTLA-4 and allow the T cells to kill cancer cells. Ipilimumab is a type of CTLA-4 inhibitor being studied to treat advanced Merkel cell carcinoma.

See Drugs Approved for Merkel Cell Carcinoma for more information.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI website.

Treatment for Merkel cell carcinoma may cause side effects.

For information about side effects caused by treatment for cancer, visit our Side Effects page.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.

Follow-up tests may be needed.

As you go through treatment, you will have follow-up tests or check-ups. Some tests that were done to diagnose or stage the cancer may be repeated to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back).