Radiation therapy is the use of forms of energy, including x-rays and gamma rays, to kill cancer cells. It is generally reserved for advanced cases where surgery is not possible or may be complicated. It is also used to relieve symptoms of melanoma that has metastasized to areas such as the brain or bone. Although an unproven treatment, radiation may be targeted to the regional lymph node basin to prevent tumor recurrence after surgery.

Radiation therapy is usually reserved for advanced cases of melanoma where surgery is not possible or may be complicated. It is rarely used to treat primary melanoma, except in cases where patients are poor candidates for surgery or refuse surgical treatment.

The main role of radiation therapy in melanoma patients is palliation (the relief of symptoms) of metastasis. Although radiation cannot cure advanced melanoma, it frequently can shrink tumors that cause discomfort. Radiation is the primary way to treat brain metastases. The goal is to relieve symptoms such as partial paralysis, headaches, and seizures.