Radiation Therapy for Merkel Cell Carcinoma (MCC)

Radiation therapy for Merkel cell carcinoma uses high-energy rays (like x-rays) or particles (such as electrons) to kill the cancer cells. The radiation is focused from outside the body onto the tumor.

When is radiation therapy used for Merkel cell cancer (MCC)?

Radiation therapy can sometimes be very helpful in treating Merkel cell carcinoma (MCC) in these situations:

• To treat the area of the main (primary) skin tumor after surgery to try to kill any cancer cells that might have been left behind. (You may hear this called adjuvant radiation.) This is especially important if there’s a high chance that the cancer will come back (such as if the main tumor was large, or if the doctor isn't sure it all was taken out).
• To treat the main tumor if surgery isn't an option, such as if a person isn’t healthy enough for surgery or the tumor is in a place where not all of it can be removed.
• To treat the lymph nodes near the main tumor. If a sentinel lymph node biopsy (or other type of biopsy) found cancer in the lymph nodes, if the results of the biopsy were not clear, or if a biopsy wasn't done, radiation therapy is often given to the lymph nodes in the area. This might be done after a lymph node dissection, or it might even be done instead of a lymph node dissection.
• To help treat MCC that has come back (recurred) after surgery, either in the skin or lymph nodes.
• To help treat MCC that has spread to distant parts of the body, often along with other treatments. In this case, radiation is used to help shrink or slow the growth of the cancer and/or to help ease symptoms caused by its spread, but it’s not expected to cure the cancer.

How is radiation therapy given for Merkel cell cancer (MCC)?

When used to treat Merkel cell carcinoma, radiation is usually given 5 days a week for many weeks. The length of treatment might be shorter if the radiation is being used to relieve symptoms caused by cancer spread.

Before treatments start, your radiation team will take careful measurements to decide the proper dose of radiation and know exactly where to aim the radiation beams. This planning session is called simulation.

Getting radiation treatment is a lot like getting an x-ray, but the radiation is stronger and aimed precisely at the cancer. The treatments don't hurt. Each one lasts only a few minutes, though the set-up time – getting you into place for treatment – takes longer.

Possible side effects of radiation therapy

Common side effects depend on what part of the body the radiation is aimed at and can include:

• Sunburn-like skin problems or changes in skin color in treated areas
• Hair loss in areas where the radiation enters the body
• Fatigue
• Nausea (if the radiation is aimed at the abdomen)

These often get worse as treatment goes on and slowly go away after treatment ends.

Radiation therapy can also raise the risk of getting another type of cancer in the treated area. If this happens, it’s usually many years after treatment.