Radiation therapy is? often used to treat tumors that have not yet spread to other parts of the body.? It kills or shrinks cancer cells through the use of? high-energy rays,? or x-rays. Because radiation affects both cancer and healthy cells, it? is given over a period of time to let healthy cells heal before the patient receives the next treatment.

Radiation therapy? can be used to help cancer patients in many different ways.? It may be used to shrink tumors? before surgery so they are easier to remove (neoadjuvant therapy).? It may also be? given after the surgery to kill any cancer cells left in the body (adjuvant therapy). Finally, it may be used to? stop the symptoms of advanced cancer, by shrinking tumors that cause pain or make it hard for a person to breath.? ?

External Beam Radiation Therapy

Patients can receive radiation therapy from the outside of the body in a process known as external beam radiation. The radiation source? is placed outside of the body and a beam of radiation is sent to certain areas of the body. External beam radiation can be used to treat a large area and can help destroy a tumor and any nearby cancer cells.? New advances in external beam radiation therapy have made this type of treatment more effective and reduced the number of side effects.

Internal Radiation Therapy (brachytherapy)

Internal radiation therapy? sends? very powerful radiation to a small area, killing most or all of the cancer cells? in that area.? ? Usually, radioactive seeds or pellets are put directly into the tumor or into the? area of the body where the tumor is located.

Side Effects

Side effects of radiation therapy are usually related to the radiation site. They? may include feeling tired,? rashes, swelling of the lining of the mouth (mucositis), nausea, vomiting, and diarrhea. Radiation therapy has also been known to? cause development of second cancers within 10 to 15 years after treatment.