Radiation therapy treats cancer by using high energy to kill
tumor cells. The goal is to kill or damage cancer cells without
hurting healthy cells. Different people have different side
effects with radiation. You may have little or only mild side
effects from your treatment; someone else may have many or very
severe side effects. Unfortunately, it's impossible to predict
who will have what side effects. In addition, the specific side
effects you may have depend on the type of radiation being used,
the dose of radiation, the area of the body that's being
targeted, and the state of your health. Note: Some citations in
the text of this section are followed by a level of evidence.
The PDQ editorial boards use a formal ranking system to help the
reader judge the strength of evidence linked to the reported
results of a therapeutic strategy. (Refer to the PDQ summary on
Levels of Evidence for more information.) The most common sites
of metastasis for pheochromocytoma or extra-adrenal
paraganglioma are lymph nodes, b