Comprehensive Cancer Care Services

Overview of Cancer | Treatment Options| Radiation Therapy

Radiation therapy is usually administered in the form of high-energy beams that deposit the radiation dose in the body where cancer cells are located. Radiation therapy, unlike chemotherapy, is considered a local treatment. This means that cancer cells are only killed at the location in the body where the radiation is delivered, called the radiation field. If cancer exists outside the radiation field, those cancer cells are not destroyed by the radiation.

Radiation therapy uses high-energy rays to kill cancer cells. For some types of cancer, radiation therapy may be used instead of surgery as the primary treatment. Radiation therapy also may be given before surgery (neoadjuvant therapy) to shrink a tumor so that it is easier to remove. In other cases, radiation therapy is given after surgery (adjuvant therapy) to destroy any cancer cells that may remain in the area. Radiation also may be used alone, or along with other types of treatment, to relieve pain or other problems if the tumor cannot be removed.

Radiation therapy works by damaging the DNA in the cancer cell, thereby disabling the cancer cells from reproducing and growing. The cancer cells then die and the cancer shrinks. The objective of radiation therapy is to kill enough cancer cells to maximize the probability of cure and minimize the side effects. Under some circumstances, radiation therapy may also be used as palliation, or palliative care, which is aimed at reducing symptoms but not curing the disease.

This information is intended to help educate you about your treatment options and to facilitate a mutual or shared decision-making process with your radiation oncologist.

Radiation Therapy Delivery Techniques

Radiation therapy may be delivered externally or internally. External radiation delivers high-energy rays directly to the cancer from a machine outside the body. Internal radiation, or brachytherapy, is the implantation of a small amount of radioactive material (seeds) in or near the cancer. Radiation can also be delivered as an isotope into a vein, as in the use of radioactive iodine for the treatment of thyroid cancer.

Side Effects and Management