Radiation treatment is the use of a certain type of energy (radiation) from X-rays, gamma rays and electrons to destroy cancer cells. In high doses, radiation destroys cells in the area being treated. It does this by damaging the DNA (genetic information) in cancer cell genes, making it impossible for them to grow and divide. During radiation treatment, both cancer cells – which are growing in an uncontrolled way – and healthy cells are affected, but most healthy cells can repair themselves.
In some cases, patients may receive radiation treatment alone, without surgery or other treatments. Some patients may receive radiation treatment and chemotherapy at the same time (often called “chemoradiation”). For some types of cancer, the combination of chemotherapy and radiation may destroy more cancer cells (increasing the likelihood of a cure), but it may also cause more side effects.
Patients may receive radiation therapy before, during or after surgery. The timing of radiation treatment depends on the type of cancer being treated and the goal of treatment (cure or to lessen symptoms):
Radiation therapy given before surgery is called pre-operative or neoadjuvant radiation. Neoadjuvant radiation may be given to shrink a tumor so it can be removed by surgery and be less likely to return after surgery.
Radiation given after surgery is called post-operative or adjuvant radiation treatment.