Radiation is often used to treat pituitary tumors that come back after surgery. It may also be used to treat pituitary tumors that cause symptoms that medication cannot relieve. Sometimes, if a tumor is very large, the surgeon will remove as much as safely possible (called debulking surgery), and then the rest of the tumor will be irradiated.
Radiation for pituitary tumors can be given in different ways. Conventional radiation is given from a machine outside the body. The radiation is directed at the pituitary and is given five times a week for several weeks with rest on weekends. However, this type of radiation works slowly, and it may take a few years for the tumor's growth and hormone production to come under control. Here are other types of radiation:
Stereotactic radiation. This is a form of radiation that precisely targets the tumor by directing beams at it from several different angles. This method makes it possible to give a higher radiation dose safely and also to radiate the tumor and not the entire brain. It can also prevent a low decrease in mental sharpness that can happen many years after conventional radiation. This kind of radiation cannot be used if the tumor is near important nerves, such as the optic nerve.
Proton beam radiation. This type of radiation therapy uses a different type of beam than the others. It can focus directly on the pituitary tumor and may expose nearby healthy tissues to less radiation. But it is only used in a select few medical centers because it requires very specialized equipment.