The SBRT medical abbreviation stands for stereotactic body radiation therapy, a way of aiming very precise, high dose radiation at a tumor in the body over a small number of treatments, usually one to five. Stereotactic refers to locating a target exactly in three dimensions.
You will see SBRT in oncology consult notes, radiation plans and tumor board summaries. It is closely related to standard radiation therapy, often written XRT, but works on a much more concentrated schedule. This page explains how it differs, how notes describe it, and what words such as fraction and Gy mean.
At a glance
Stands for
Stereotactic body radiation therapyAlso called
SABR, stereotactic ablative radiotherapyUsed in
Radiation oncologyTypical schedule
Usually 1 to 5 treatments, called fractionsCommon targets
Lung, liver, spine, prostate, pancreas, limited spread of cancerDo not confuse with
SRS (radiosurgery for the brain) and XRT (radiation in general)
How SBRT works
Ordinary radiation courses often spread smaller daily doses over several weeks. SBRT gives much larger doses per session but shapes the beams so tightly around the tumor that nearby healthy tissue receives far less. To do that safely, the team uses detailed imaging, careful planning and devices that keep the body still or track breathing.
Before treatment, a planning scan, often a CT, maps the tumor and the organs around it. Small markers may be placed near some tumors to guide the beams. Each session usually lasts longer than a standard radiation visit, but the full course is over in days rather than weeks.
Decoding an SBRT plan line
A radiation plan squeezes many details into a single line. This example shows the usual parts.
| Plan text | Meaning |
|---|---|
| SBRT | Stereotactic body radiation therapy |
| RUL nodule | A spot in the lung's right upper lobe |
| 50 Gy | The total radiation dose, in gray units |
| 5 fractions | Split into five treatment sessions |
| every other day | The spacing of those sessions |
At a tumor board: "Early stage NSCLC, not a surgical candidate, recommend SBRT." The team is suggesting focused radiation as an alternative for someone whose health makes lung surgery risky. Doses here are examples of format only.
Where the SBRT medical abbreviation shows up most
Lung cancer is one of the best known uses, especially small early tumors in people who cannot have or do not want surgery. SBRT is also used for some liver tumors, including HCC, tumors in or near the spine, prostate cancer, kidney and pancreas tumors, and for a few spots of cancer that have spread, sometimes called oligometastatic disease.
Whether it fits a particular person depends on the tumor type, size, location and the person's overall health. Radiation oncologists make that call with surgeons and medical oncologists, often after a biopsy confirms the diagnosis.
Side effects as notes describe them
Because the beams are so focused, many people have fewer side effects than with longer courses, but effects still occur and depend on the area treated. Notes may mention tiredness, skin redness, cough or lung inflammation called pneumonitis after chest treatment, or stomach upset after abdominal treatment.
Follow up scans check how the tumor responds. Changes on imaging after SBRT can look like scarring for months, so radiologists and oncologists compare several scans over time before drawing conclusions.
Questions to bring to the radiation team
- How many SBRT sessions are planned, and how long will each take?
- Will markers, a body mold or breath holding be part of treatment?
- Which side effects are most likely for this area of the body?
- When will the first follow up scan happen?
The explanation here is general. Your radiation oncologist and care team can say whether and how stereotactic treatment applies to your situation.
Frequently asked questions
What does SBRT stand for in cancer care?
It stands for stereotactic body radiation therapy. It delivers high, precisely targeted radiation doses to tumors outside the brain over a small number of sessions.
Is SBRT the same as SABR?
Yes. Stereotactic ablative radiotherapy, or SABR, is another name for the same type of treatment, and some centers prefer that term.
How many sessions does SBRT take?
Usually between one and five sessions, called fractions. The exact number depends on the tumor and its location, and the radiation team sets the schedule.
Does SBRT involve surgery?
No. Despite the word stereotactic and its listing near procedures, it uses radiation beams from outside the body, with no incision.