Radiation therapy, sometimes called radiotherapy or irradiation, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation oncologists may use radiation therapy to try to cure cancer, to control the growth of the cancer or to relieve symptoms, such as pain.

Radiation therapy works by damaging the DNA within cancer cells and destroying the ability of the cancer cells to reproduce. When these damaged cancer cells die, the body naturally eliminates them. Normal cells are also affected by radiation, but they are able to repair themselves in a way that cancer cells cannot.

Sometimes radiation therapy is the only treatment a patient needs, and other times it is only one part of a patient’s treatment. For example, prostate and larynx cancer are often treated with radiation alone, but a woman with breast cancer may be treated with surgery, radiation therapy and chemotherapy.

Sometimes radiation therapy is used as adjuvant therapy to make your primary treatment more effective. For example, you can be treated with radiation therapy (the adjuvant treatment) before surgery (the primary treatment) to help shrink the cancer and allow less radical surgery than would otherwise be required, or you may be treated with radiation after surgery to destroy microscopic cells that may have been left behind. 

A radiation oncologist may choose to use radiation therapy in a number of different ways. Sometimes the goal is to cure the cancer. In this case, radiation therapy may be used to:

• Destroy tumors that have not spread to other parts of your body.

• Reduce the risk that cancer will return after you undergo surgery or chemotherapy by killing tiny cancer cells that may remain.

• In other cases, the goal is to reduce the symptoms caused by growing tumors and to improve your quality of life. When radiation therapy is administered for this purpose, it is called palliative care or palliation. In this instance, radiation may be used to:

• Shrink tumors that are interfering with your quality of life, such as a lung tumor that is causing shortness of breath.

• Alleviate pain by reducing the size of your tumor.

It is important for you to discuss the goal of your treatment with your radiation oncologist.

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