Stereotactic Body Radiation Therapy (SBRT and Stereotactic Radiosurgery (SRS)

What are SBRT and SRS? Are they the same thing?

Stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) precisely target tumors with a high dose of radiation. Both treatments are noninvasive, meaning that no surgery is actually involved, and take place over one to five sessions. They allow for higher doses of radiation over a shorter period of time compared to conventional radiation therapy.

While SBRT and SRS are very similar, they differ in the number of treatments they require and the area of the body being treated. With SBRT, patients receive radiation over one to five treatment sessions targeting tumors throughout the body, excluding the brain and spine. In contrast, SRS typically involves a single treatment session targeting tumors in the brain or spine.

How are SBRT and SRS given?

Prior to undergoing SBRT or SRS, you will have a CT scan or an MRI to map out your tumor. These 3D images will help your treatment team locate the tumor and define its exact size and shape. A linear accelerator (a machine that uses x-rays to target tumors) then rotates around your body, delivering precise beams of high-dose radiation to the tumor from different angles.

Markers may need to be placed into your tumor in order to track it during treatment. You may also need to have small ink tattoos placed on your skin to help position your body for treatment. Additionally, you may need a special device to keep your body from moving during treatment, such as a head frame or a plastic mask.

Who should consider SBRT and SRS?

SBRT and SRS are particularly effective in treating small, well-defined tumors that are few in number. These therapies can often be good alternatives to surgery. Because SBRT and SRS deliver such a high dose of radiation, they are best for patients with localized cancers. SBRT and SRS may also be good treatment options if you:

• Are unable to undergo surgery
• Have a tumor located close to vital organs
• Have certain neurological conditions

SBRT is used to treat early-stage non-small-cell lung cancer and pancreatic cancer, as well as certain types of metastatic cancer. SRS is used to treat smaller brain tumors.