Radiation Therapy for Merkel Cell Carcinoma

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

When might radiation therapy be used?

Not all doctors agree on exactly when radiation therapy should be used for Merkel cell carcinoma (MCC), but it might be used 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. This is especially important if there’s a higher chance that the cancer will come back (such as if the main tumor was large, or if the doctor is not sure it was all removed with surgery).
  • To treat the main tumor if surgery is not an option for some reason, such as if a person isn’t healthy enough for surgery.
  • 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 was not 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, the radiation is used to help shrink or slow the growth of the cancer and/or to relieve symptoms caused by its spread, but it’s not expected to cure the cancer.

How is radiation therapy given?

When used to treat MCC, radiation is usually given 5 days a week for several weeks. The length of treatment might be shorter if it’s only being used to relieve symptoms caused by the cancer spread.

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

Getting radiation treatment is much like getting an x-ray, but the radiation is stronger and aimed more precisely at the cancer. The procedure itself is painless. Each treatment lasts only a few minutes, although the set-up time – getting you into place for treatment – takes longer.

Possible side effects of radiation therapy

Common side effects depend on where the radiation is aimed and can include:

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.

To learn more, see the Radiation Therapy section of our website.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: April 13, 2015 Last Revised: May 23, 2016

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