Stereotactic Body Radiation Therapy (SBRT)

What is stereotactic body radiation therapy?

Stereotactic body radiation therapy (SBRT) is a cancer treatment that delivers highly concentrated doses of targeted radiation to a single or solitary tumor. A type of stereotactic radiosurgery, SBRT is a technological advancement in the field of radiation therapy.

Unlike conventional radiation, SBRT delivers the optimal dosage of radiation over a shorter time period (days, not weeks). It delivers large radiation doses to the tumor itself while limiting the amount of radiation going to nearby healthy tissue and organs, where it could cause damage.

What cancers are treated with SBRT?

Radiation oncologists use SBRT to treat small tumors. Your provider may also recommend SBRT if you have health problems that prevent you from getting surgery.

SBRT is a noninvasive alternative to surgery for treating:

• Primary cancers: The original tumor.
• Oligometastatic cancers: Tumors that have spread from the primary location, but that are still small and few enough in number for removal.

Cancer types treated with stereotactic body radiation therapy include:

• Lung cancer.
• Prostate cancer.
• Liver cancer.
• Pancreatic cancer.

How should I prepare for SBRT?

Your healthcare provider will review your medical history and check your current health to ensure you’re a good candidate for SBRT. They’ll explain what happens during the procedure, including benefits and potential risks. If you agree that SBRT is the right option, you’ll sign an informed consent form.

While everyone’s experience may be a bit different, your provider will likely let you know:

• If you’ll need someone with you: Most people can drive themselves home afterward, but it may be a good idea to have a loved one with you for moral support.
• If you need to fast or take medications: They’ll let you know when to quit eating and drinking the night before your session. Depending on your situation, you may need to take anti-nausea, anti-inflammatory (NSAIDs) or anti-anxiety medications beforehand.
• What to wear: It’s a good idea to wear comfortable clothes that are easy to take off and put on, so you can slip in and out of a hospital gown easily. You may need to leave wigs, jewelry, glasses and dentures at home.
• How long treatment should take: Treatment sessions typically last between 15 minutes to more than an hour, but times vary.
• How to manage anxiety: Cancer creates stress, whether you’re anticipating test results or waiting to be called in for treatment. Ask your provider for suggestions about managing pre-treatment stress. They may recommend you bring a book, magazine or crossword puzzle with you. They may provide anti-anxiety medications that can help.

Treatment simulation

Treatment simulation for SBRT happens before the actual procedure. It allows your healthcare provider to map out the target treatment area and start designing the treatment.

Simulation typically involves:

• Getting imaging tests: You may have CT scans, MRIs and X-rays that help your provider identify the tumor’s precise location. This allows them to program the machine to deliver small beams of radiation that target the tumor.
• Being placed into position: Your provider will determine how to place you on the treatment table. They may make marks on your skin on or near the tumor, so they know where to aim the radiation beams.
• Having molds or casts made: Your provider may fit you for an immobilization device, like a mold or cast, that goes on the part of your body where the tumor is located. These devices help you stay still during treatment. They ensure you’re in the same position for each session.

Your simulation session is a great opportunity to talk to your provider about the mapping process, like whether you’re in a comfortable position or if being unable to move makes you feel anxious. Based on how you’re feeling, your provider can take steps to ensure you’re as comfortable as possible during treatment.

What happens during SBRT?

Stereotactic body radiation therapy doesn’t hurt and is much like having an X-ray. Your healthcare provider will take steps to ensure your comfort. Still, remember that you can stop the treatment session any time you start feeling anxious or uneasy.

During treatment:

1. You’ll lie on a table similar to one used for the simulation. A radiation technician will position you so you’re placed exactly as you were before.
2. Technicians will operate the machine from a separate room. The technicians will work under the supervision of your radiation oncologist. They’ll see you on a screen, and you’ll be able to communicate over an intercom.
3. The machine will deliver the radiation. The radiation will come from a wide arm on the machine that hangs over you. The arm will move around you at different angles. As it does, it delivers multiple small beams of high-dose radiation that conform to the shape of your tumor. That way, only the tumor receives the radiation.

You won’t feel anything during treatment, but you may hear some noise from the machine as it moves.

What happens after SBRT?

The technicians will help you up from the treatment table.

Depending on your treatment schedule, this may be your only session, or you may need a few others. SBRT treatment usually involves one to five sessions that take place over one to two weeks.

Tumors that respond well to treatment typically shrink over the next few months.

What are some typical SBRT side effects?

Side effects vary, depending on the type of cancer and your overall health:

• SBRT for lung cancer: Most people don’t feel anything unusual after treatment. In the first weeks, you may feel very tired, have a mild cough and bring up phlegm. Talk to your healthcare provider right away if you have any sudden or unexpected breathing changes.
• SBRT for prostate cancer: You may feel an urgent need to pee or feel you have to go more often. You may notice bowel changes, including when and how often you poop or if it hurts to poop. Talk to your healthcare provider about managing these short-term changes.
• SBRT for liver and pancreatic cancer: You may feel nauseated and have diarrhea. Your healthcare provider will suggest medications and other things, like changing what you eat, so this side effect impacts your daily life less.

What are the benefits of SBRT?

Studies show that SBRT is an effective treatment for some cancers. SBRT lets healthcare providers target tumors while limiting the radiation’s impact on nearby organs and tissues. It allows them to remove tumors with near-surgical precision, but without surgery.

SBRT also requires fewer treatments than conventional radiation therapy. This may decrease your risk of side effects.

How successful is SBRT?

Stereotactic body radiation therapy is an effective alternative to surgery in some cases. For example, recent studies show that SBRT is just as effective as surgery for treating some early-stage lung and prostate cancers. For some people, SBRT is also a noninvasive alternative to surgery for slowing tumor growth in cancers that have spread.

What are the risks or complications of SBRT?

In rare cases, SBRT can cause long-term side effects if the radiation damages healthy tissue. When this happens, the side effects depend on which organ was impacted by radiation exposure. But one of the key benefits of SBRT is the precise way in which it’s delivered. Your care team will design your treatment so the radiation impacts tumors, not healthy tissue.

All radiation therapy comes with the very small potential that you’ll develop cancer from your treatment. But another benefit of SBRT is that treatment limits the impact radiation has on healthy organs and tissues. Your healthcare provider will check you regularly for any new or recurring cancer.

What is the recovery time?

Most people can go back to work or resume other daily activities one or two days after SBRT treatment. You should be able to resume eating and drinking as usual immediately after the procedure.

When should I see my healthcare provider?

You’ll likely have a routine schedule of follow-ups after your treatment. At these appointments, your healthcare provider can update you on how SBRT is working, and you can let them know about your experiences after treatment. But you should call your healthcare provider if your side effects are different from what you expected.

Contact your healthcare provider right away if you suddenly feel short of breath after SBRT for lung cancer.

What is the difference between SBRT and IMRT?

SBRT and intensity-modulated radiation therapy (IMRT) are both types of external beam radiation therapy (EBRT). This means they use a machine outside of your body to direct radiation toward a tumor.

While both use technology to target tumors with precision (so there’s minimal radiation exposure to surrounding healthy tissue), IMRT is more commonly used in conventional EBRT. Conventional EBRT can treat larger targets (including the cancer and the areas where it’s spread) than SBRT. SBRT treats select small tumors only using a stronger dose. The stronger dosage shortens treatment time from several weeks (as with conventional EBRT) to just one to five sessions.

Your healthcare provider may recommend you receive SBRT, IMRT or (in some cases) both types. Ask them to explain the benefits and potential risks of the treatment options they recommend.