Radiation Therapy for Pituitary Tumors

Radiation therapy for pituitary tumors involves sending beams of radiation from an external machine, through the skin and skull toward the tumor. When the beams of radiation reach the tumor, they can destroy the tumor cells by damaging their DNA.

Pituitary tumor expert Kathryn Beal

Radiation therapy can be used in one of several ways for pituitary tumors. It may be recommended after pituitary tumor surgery to prevent regrowth of a tumor. Radiation may also be used as the sole treatment if the tumor cannot be removed surgically, or if the tumor regrows after surgery.

The radiation therapy team at Memorial Sloan Kettering is highly experienced in caring for people with pituitary tumors, and works closely with the other members of your care team. They have access to every form of modern radiation therapy available and will customize a treatment plan so precise that it factors in the size and shape of your tumor to the millimeter.

Their goal is to not only eliminate the tumor cells but to prevent short-term and long-term side effects of treatment by keeping the healthy tissue around the tumor, including the brain and optic nerves, safe.

Stereotactic Radiosurgery (SRS) and Stereotactic Radiotherapy (SRT) for Pituitary Tumors

Stereotactic radiosurgery (SRS) is a high-dose treatment developed by experts at MSK. It allows radiation to be delivered with greater precision to the tumor than conventional radiation therapy. First, a 3-D outline of the tumor is created using MRI scans and CT scans. Then a team of radiation experts, including doctors and physicists, uses a computerized system to shape the radiation beam to match the 3-D outline. SRS makes it possible for us to spare surrounding healthy brain tissue from any significant dose of radiation. Oftentimes, our patients require only one to five treatments with SRS.  

Likewise, stereotactic radiotherapy (SRT) delivers a highly focused type of radiation therapy plan, in many small, or fractionated, doses of radiation. This approach is used when the target is very close to, or touching, critical areas such as the optic structures. 

With both SRS and SRT, we take X-rays or CTs prior to treatment to ensure that the patient is precisely positioned. This extra step allows us to match the treatment position with the radiation therapy treatment plan to within the millimeter. 

Intensity-Modulated Radiation Therapy (IMRT) for Pituitary Tumors

Intensity-modulated radiation therapy (IMRT) is another form of radiation treatment we sometimes recommend for people with pituitary adenomas. Like SRS, it provides greater precision than traditional forms of radiation therapy, and was developed by MSK’s radiation therapy experts.

Prior to treatment, we map the tumor in 3-D using a CT scanner. Then a team of radiation therapy experts, including doctors and physicists, inputs that information into advanced computer programs to calculate treatment and deliver radiation directly to the tumor from different angles.

Proton Therapy for Pituitary Tumors

Memorial Sloan Kettering is one of a limited number of centers nationwide offering proton therapy. Our team is highly experienced in this approach. 

Proton therapy is delivered by a device called a cyclotron, which sends a high-energy beam of protons through the skin toward the tumor. Because the proton beams do not penetrate beyond the tumor, proton therapy may lower your risk for treatment-related side effects caused by exposing normal tissue to radiation. Proton therapy may also allow the use of a higher radiation dose to the tumor, which is sometimes needed to maximize the chance of destroying it.

Before starting proton therapy, we outline the precise dimensions of the tumor using an imaging scan such as MRI.