Stereotactic Radiotherapy (SABR)

Stereotactic Ablative Body Radiotherapy (SABR), also known as Stereotactic Body Radiotherapy (SBRT), is one of the most advanced forms of radiation therapy available.

Unlike conventional radiotherapy, which is usually delivered over several weeks, SABR delivers very high doses of radiation with exceptional precision over just 1–8 treatments. This allows doctors to destroy cancer cells while minimising radiation exposure to surrounding healthy organs.

SABR combines advanced imaging, sophisticated treatment planning and highly accurate treatment delivery to target tumours with millimetre precision. It is most commonly used for:

• Early-stage lung cancer
• Prostate cancer
• Liver tumours
• Kidney cancer
• Adrenal tumours
• Pancreatic cancer (in selected patients)
• Spine tumours
• Oligometastatic cancer (where cancer has spread to only a few sites)

For many patients, SABR offers outcomes comparable to surgery while avoiding an operation, hospital stay and lengthy recovery.

Yes. The terms SABR (Stereotactic Ablative Body Radiotherapy) and SBRT (Stereotactic Body Radiotherapy) describe the same treatment.

In Australia and the United Kingdom, the term SABR is more commonly used because it reflects the aim of delivering a high enough dose to completely destroy (ablate) the tumour. In North America, the term SBRT is more widely used. Although the names differ, the treatment technique is the same.

The biggest differences are precision, dose and treatment duration.

Traditional radiotherapy usually delivers smaller daily doses over several weeks. SABR delivers much higher doses during each treatment, allowing the entire course to be completed in only a few sessions. Compared with conventional radiotherapy, SABR offers:

• Greater treatment precision
• Better protection of nearby healthy organs
• Fewer treatment visits
• Higher biological doses to the tumour
• Excellent local tumour control for many cancers

Because of the high doses used, SABR requires meticulous planning, advanced imaging and strict quality assurance.

SABR is suitable for many cancers, although not every patient is a candidate. Common indications include:

• Early-stage lung cancer
• Prostate cancer
• Kidney cancer
• Liver cancer
• Adrenal metastases
• Lung metastases
• Liver metastases
• Spine metastases
• Lymph node metastases
• Pancreatic cancer in selected cases
• Oligometastatic cancer

SABR is also increasingly being used for carefully selected recurrent cancers. Whether SABR is appropriate depends on the tumour's size, location, movement during breathing, previous treatments and your overall health.

SABR is most appropriate for patients with:

• Small, well-defined tumours
• Limited numbers of tumours
• Tumours that can be accurately targeted
• Good overall health
• Tumours located where surrounding organs can be safely protected

Many patients choose SABR because they wish to avoid surgery, while others may have medical conditions that make surgery too risky. Every patient should undergo an individual assessment by a radiation oncologist experienced in SABR before treatment is recommended.

Oligometastatic cancer refers to cancer that has spread to only a small number of sites, typically between one and five tumours — though research is ongoing into whether this upper limit should be higher.

Research suggests that some patients with oligometastatic disease benefit from SABR. Treating all visible sites of disease may improve survival, maintain quality of life, and reduce the need for additional systemic therapy. Whether SABR is appropriate depends on the type of cancer and your overall treatment plan.

Sometimes. If a new tumour develops or cancer returns in a different location, another course of SABR may be possible.

Whether repeat treatment is appropriate depends on:

• The previous radiation dose
• The location of the new tumour
• Nearby organs
• The time since previous treatment
• Your overall health

Each situation requires careful individual assessment.

There is no single "best" machine. Excellent SABR can be delivered using several modern technologies, including:

• Varian TrueBeam
• Varian Edge
• CyberKnife
• Halcyon
• Ethos
• MR-LINAC systems
• Other advanced linear accelerators

Each platform has particular advantages. For most patients, the experience of the treating team, the quality of treatment planning and rigorous quality assurance are more important than the brand of machine. Choosing an experienced centre that performs SABR regularly is often more important than choosing a particular technology.

Choosing where to have radiotherapy is an important decision. Useful questions include:

• What technology will be used and why?
• What are the expected benefits and risks for my situation?
• What are the alternatives to SABR?
• Will I receive follow-up imaging after treatment?
• What clinical trials might be appropriate for me?

Every patient's situation is unique. A consultation can help you understand whether SABR is the most appropriate treatment and what outcomes are expected.