Radiation therapy uses high-energy x-rays or particles to destroy cancer cells or slow their rate of growth. Radiation therapy can be used in many ways to treat and oropharyngeal cancers:

• It can be used as the main treatment for small cancers.
• People with larger cancers may need both surgery and radiation therapy or a combination of radiation therapy and chemotherapy or a targeted drug.
• After surgery, radiation therapy can be used, either alone or with chemotherapy, as an additional (adjuvant) treatment to try to kill any cancer cells that might not have been removed during surgery. This is called adjuvant radiation therapy. Most experts agree that radiation used this way should be started within 6 weeks of surgery.
• Radiation may be used (along with chemotherapy) to try to shrink some larger cancers before surgery. This is called neoadjuvant therapy. In some cases this makes it possible to use less extensive surgery and remove less tissue.
• Radiation therapy can also be used to help ease symptoms of advanced cancer, such as pain, bleeding, trouble swallowing, and problems caused by bone metastases (cancer that has spread to bones).