Radiation Therapy for Melanoma Skin Cancer

Radiation therapy uses high-energy rays (such as x-rays) or particles to kill cancer cells.

When might radiation therapy be used?

Radiation therapy is not needed for most people with melanoma on the skin, although it might be useful in certain situations:

• It might be an option to treat very early stage melanomas, if surgery can't be done for some reason.
• Radiation can also be used after surgery for an uncommon type of melanoma known as desmoplastic melanoma.
• Sometimes, radiation is given after surgery in the area where lymph nodes were removed, especially if many of the nodes contained cancer cells. This is to try to lower the chance that the cancer will come back.
• Radiation can be used to treat melanoma that has come back after surgery, either in the skin or lymph nodes, or to help treat distant spread of the disease.
• Radiation therapy is often used to relieve symptoms caused by the spread of the melanoma, especially to the brain or bones. Treatment with the goal of relieving symptoms is called palliative therapy. Palliative radiation therapy is not expected to cure the cancer, but it might help shrink it or slow its growth for a time to help control some of the symptoms.

How is radiation therapy given?

The type of radiation most often used to treat melanoma, known as external beam radiation therapy, focuses radiation from a source outside of the body on the cancer.

The treatment schedule can vary based on the goal of treatment and where the melanoma is. Before treatments start, your radiation team will take careful measurements to find the correct angles for aiming the radiation beams and the proper dose of radiation. This planning session is called simulation.

Treatment is much like getting an x-ray, but the radiation is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, although the setup time – getting you into place for treatment – usually takes longer.

Stereotactic radiosurgery (SRS)

SRS is a type of radiation therapy that can sometimes be used for tumors that have spread to the brain. (Despite the name, there is no actual surgery.) High doses of radiation are aimed precisely at the tumor(s) in one or more treatment sessions. There are 2 main ways to give SRS:

• In one version, a machine called a Gamma Knife^® focuses about 200 thin beams of radiation on the tumor from different angles over a few minutes to hours. The head is kept in the same position by placing it in a rigid frame.
• In another version, a linear accelerator (a machine that creates radiation) that is controlled by a computer moves around the head to deliver radiation to the tumor from many different angles over a few minutes. The head is kept in place with a head frame or a plastic face mask.

These treatments can be repeated if needed.

Stereotactic body radiation therapy (SBRT)

This approach is similar to SRS (using a linear accelerator), but it can be used to treat tumors in other parts of the body.

Possible side effects of radiation therapy

Side effects of radiation are usually limited to the area getting radiation. Common side effects can include:

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

Often these go away after treatment.

Radiation therapy to the brain can sometimes cause memory loss, headaches, trouble thinking, or reduced sexual desire. Usually these symptoms are minor compared with those caused by a tumor in the brain, but they might still affect your quality of life.