Stereotactic Body Radiotherapy Procedure
Purpose of Treatment
Stereotactic body radiotherapy (SBRT), also known as stereotactic ablative radiotherapy (SABR), is a precise radiation therapy used to treat tumors in the lungs, spine, liver, neck, lymph nodes, adrenal glands, and other soft tissues.
It targets both cancerous and benign tumors, and is commonly used in cancer care for lung, liver, prostate, pancreatic, and spine cancers, as well as oligometastatic disease. A related treatment, stereotactic radiosurgery, is often used for brain or central nervous system tumors.
SBRT is typically recommended for small, localized tumors that are difficult or unsafe to remove surgically—either because of a patient’s health condition or the tumor’s location near vital organs. It may also be used for tumors that have recurred after prior treatment.
Side Effects and Possible Complications
SBRT, like all forms of radiation therapy, can cause side effects. These effects can be grouped by when they appear:
Short-Term Side Effects
- Fatigue: Many patients feel tired for a few days following treatment.
- Swelling: Some notice temporary swelling and increased pain near the treated area.
- Nausea or Vomiting: These symptoms may happen if the area treated is close to the bowel or liver.
- Skin Irritation: The skin at or around the treatment site can become dry, itchy, or red.
Long-Term and Rare Side Effects
- Bone Weakness: Treated bones might become weaker and could break more easily.
- Organ Changes: Possible late changes can occur in the bowel, bladder, lungs, spinal cord, or other nearby organs.
- Swelling (Lymphedema): Especially if lymph nodes are involved.
- Second Cancer: There is a small chance of developing a new cancer due to radiation exposure.
| Time Frame | Example Side Effects |
|---|---|
| Early (within days) | Fatigue, nausea, skin changes, swelling |
| Late (months/years) | Bone damage, lymphedema, organ changes |
The likelihood and type of side effects depend on the location of the tumor, the dose of radiation, and each individual’s health. Radiation oncologists monitor patients closely to address any symptoms.
Getting Ready for SBRT
Preparation for SBRT includes instructions and steps to help ensure safe and accurate treatment. The care team may ask patients not to eat or drink for a few hours before treatment. Discuss all current medications with the care team to determine which can be taken beforehand.
Clothing and Personal Items
- Wear comfortable, loose clothing.
- Avoid wearing jewelry, eyeglasses, contact lenses, makeup, wigs, nail polish, or dentures.
Medical Devices
- Inform the clinical team about any internal medical devices such as pacemakers, artificial valves, aneurysm clips, neurostimulators, or stents.
Treatment Simulation
- The team may schedule a planning session using a CT scan, MRI, or other imaging to create a customized treatment plan.
- Staff may use custom devices, like cushions or masks, to help keep the patient still.
- Sometimes, the team marks the skin with small tattoos or places a fiducial marker near the tumor to guide treatment.
During and After the Procedure
SBRT is performed as an outpatient procedure. No incisions or hospital stay are required. Patients usually do not need to stay overnight.
Positioning and Imaging
- The team positions the patient and may use specialized equipment to support and stabilize the body.
- Imaging (CT scan, MRI, or 4D imaging) allows doctors to see the exact shape, size, and location of the tumor. Some scans also show how the tumor moves with each breath.
Treatment Delivery
- Machines such as linear accelerators or proton therapy systems deliver focused beams of radiation from different angles.
- Most sessions last up to an hour. SBRT is typically given over 1 to 5 sessions, depending on the customized treatment plan.
- The process is painless. Adults are usually awake and can talk to staff. In special cases, the team gives medicine to relax or lightly sedate the patient, especially for children.
After SBRT
- Side effects like mild pain or nausea may appear; medication usually manages these.
- Patients can usually eat, drink, and return home the same day.
- Most people can return to regular activities within a day or two.
Sample Treatment Platforms
| Name | Technology | Common Use Areas |
|---|---|---|
| Conventional Linear Accelerator | X-ray/Photon beams | Lung, liver, spine, prostate |
| Robotic Radiotherapy System | Image-guided X-ray delivery | Brain, spine, lungs, pancreas |
| Proton Therapy System | Charged particles (protons) | Re-treated sites, near organs |
| Image-Guided Radiotherapy System | Advanced photon-based imaging | Multiple tumor locations |
Tracking Outcomes
SBRT results appear gradually. Benign tumors may shrink over 18 months to two years. In these cases, the main goal is to stop further growth. Cancerous tumors often shrink more quickly—sometimes in a matter of months. The care team monitors the tumor’s response using follow-up imaging scans and checkups.
Possible Outcomes of SBRT
- Scans show tumor shrinkage.
- Tumor growth stabilizes.
- Quality of life improves due to reduced tumor effects.
- Patients require fewer sessions compared to traditional radiation therapy.
The care team schedules regular appointments and imaging at set intervals (such as 1, 3, 6 months, or as needed) to check treatment effectiveness and watch for late side effects.
Measuring Results
| Tumor Type | Goal | Typical Time to Observe Change |
|---|---|---|
| Benign | Stop growth, shrink tumor | 18 months to 2 years |
| Cancerous (malignant) | Shrink or eliminate | A few months |
Quality of Life and Patient Outcomes
Many patients are able to resume a normal lifestyle soon after treatment. SBRT offers strong local tumor control for well-defined cases such as early-stage lung cancer, localized prostate cancer (including intermediate- and high-risk types), small brain metastases, and inoperable pancreatic tumors.
Patients with complex health needs or rare tumors may be reviewed by multidisciplinary boards or considered for clinical studies aimed at individualized care.
Summary Table: Common SBRT Locations and Indications
| Body Part | Common Tumors Treated | Notes |
|---|---|---|
| Lung | Early-stage cancer, oligometastases | Alternative to surgery |
| Liver | Primary, metastatic tumors | Especially in non-surgical cases |
| Prostate | Localized intermediate/high risk | Fewer treatments than standard |
| Spine | Metastatic or primary tumors | Protects spinal cord |
| Brain | Metastases (SRS) | Stereotactic radiosurgery |
| Pancreas | Non-operable cancer | Pain relief and control |
| Adrenal | Oligometastatic disease | Precision near organs |
A radiation oncology team provides ongoing follow-up and support after SBRT. Detailed planning, advanced imaging, and individualized care all contribute to the safety and success of this treatment.
