Stereotactic body radiation therapy (SBRT)

Overview

Stereotactic Body Radiation Therapy (SBRT) is an advanced cancer treatment that administers precise, high-dose radiation directly to a specific tumor. As a form of stereotactic radiosurgery, SBRT represents a significant technological leap in radiation therapy.

In contrast to traditional radiation methods, SBRT delivers the required radiation dose over a shorter duration, typically in a matter of days rather than weeks. This technique focuses intense radiation on the tumor while minimizing exposure to surrounding healthy tissues and organs, thereby reducing the risk of collateral damage.

Reasons for undergoing the procedure

Radiation oncologists employ SBRT to target small tumors. Your healthcare provider might also suggest SBRT if you have medical conditions that make surgery unfeasible. SBRT serves as a noninvasive alternative to surgery for treating:

• Primary cancers: The original tumor.
• Tumors that have spread from their original site but are still small and few in number, allowing for their removal.

Among the cancer types that stereotactic body radiation treatment treats are:

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

Risks

Depending on the type of cancer and your general health, side effects can vary:

• SBRT for lung cancer: Most people don’t experience anything out of the ordinary immediately after treatment. However, within the first few weeks, you may feel very fatigued, develop a mild cough, or cough up phlegm. If you notice any sudden or unexpected changes in your breathing, contact your doctor immediately.
• SBRT for prostate cancer: You might feel a strong urge to urinate or find yourself needing to go more frequently. Bowel habits may also change, such as the timing, frequency, or discomfort during bowel movements. Discuss these temporary changes with your doctor for guidance on how to manage them.
• SBRT for liver and pancreatic cancer: You may experience nausea and diarrhea. Your doctor can recommend medications and dietary adjustments to help minimize the impact of these side effects on your daily life.

In rare instances, if the radiation harms healthy tissue, SBRT may result in long-term adverse effects. The negative effects in this case vary depending on which organ was exposed to radiation. However, the specific mode of delivery of SBRT is one of its main advantages. Your doctor will arrange your care such that the radiation targets the malignancies and spares healthy tissue.

There is an extremely small chance that receiving radiation therapy will cause you to get cancer. However, limiting the amount of radiation that is exposed to healthy organs and tissues is another advantage of SBRT. Your doctor will periodically examine you to look for any signs of cancer, either new or returning.

Before the procedure

To determine whether you’re a good candidate for SBRT, your doctor will examine your past medical records and assess your present state of health. They will go over the procedure’s outcomes, advantages, and any hazards. You will sign an informed consent form if you feel that SBRT is the best course of action.

Each person’s experience may vary slightly, but generally speaking, your doctor will inform you of:

• Having someone with you: While most people are able to drive themselves home afterward, it can be comforting to have a loved one accompany you for support.
• Fasting and medication requirements: Your doctor will inform you when to stop eating and drinking the night before your session. You may also be advised to take medications, such as anti-nausea, anti-inflammatory (NSAIDs), or anti-anxiety drugs, depending on your needs.
• What to wear: It’s recommended to wear comfortable clothing that’s easy to change in and out of, allowing for a smooth transition into a hospital gown. Consider leaving wigs, jewelry, glasses, and dentures at home.
• Duration of treatment: Sessions typically last anywhere from 15 minutes to over an hour, although the exact time can vary.
• Managing anxiety: The stress of dealing with cancer is natural, whether you’re waiting for test results or your treatment session. Ask your healthcare provider for tips on easing pre-treatment anxiety. They might suggest bringing a book, magazine, or crossword puzzle to occupy your mind, or they may prescribe anti-anxiety medication to help you relax.

Treatment simulation

Before the real surgery, SBRT treatments are simulated. It enables the target treatment region to be mapped out and the treatment plan to be designed.

Typically, simulation includes:

• Undergoing imaging tests: You may need to have Computed Tomography (CT) scans, MRIs, or X-rays to help your doctor pinpoint the exact location of the tumor. These images allow them to program the equipment to direct precise radiation beams at the tumor.
• Positioning on the treatment table: Your doctor will determine the best position for you on the treatment table. They may mark your skin near the tumor site to ensure accurate targeting of the radiation beams.
• Creating molds or casts: To keep you still during treatment, your provider may fit you with an immobilization device, such as a mold or cast, placed on the area of your body where the tumor is located. These devices help maintain the same position throughout each session.
• Maximizing comfort during the simulation session: This session is an ideal time to discuss the mapping process with your doctor. If you’re uncomfortable or if staying still causes anxiety, let them know. They can make adjustments to ensure you remain as comfortable as possible during treatment.

During the procedure

Similar to an X-ray, stereotactic body radiation therapy is painless. Your doctor will make every effort to make you feel comfortable. However, keep in mind that you are free to end the treatment session if you get uncomfortable or nervous.

While receiving treatment:

• Positioning on the treatment table: You’ll lie on a table similar to the one used during your simulation. A radiation technician will position you exactly as you were before to ensure accuracy.
• Remote operation of the machine: Technicians will operate the radiation machine from a separate room, under the guidance of your radiation oncologist. They’ll monitor you on a screen, and you’ll be able to communicate with them via an intercom.
• Radiation delivery: The machine’s arm, which hangs above you, will rotate around you at different angles, delivering multiple small beams of high-dose radiation. These beams are precisely shaped to match your tumor, ensuring that only the tumor is exposed to the radiation.

During the procedure, you won’t feel anything, but the machine’s movements may make some noise.

After the procedure

You will be helped off the treatment table by the technicians.

This may be the only session you need, or you may need a few more, depending on your treatment schedule. One to five treatments spread over one to two weeks are often part of an SBRT treatment.

When a tumor responds favorably to treatment, it usually gets smaller over the following few months.

Outcome

One or two days following SBRT treatment, the majority of patients are able to return to work or resume other regular activities. After the treatment, you should be able to go back to your regular eating and drinking schedule.

In certain situations, stereotactic body radiation therapy works well in place of surgery. For instance, new research indicates that SBRT is equally efficacious as surgery in the treatment of certain early-stage prostate and lung cancers. In certain cases, SBRT can also be used as a non-invasive substitute for surgery in order to limit the growth of tumors in cancers that have spread.