Stereotactic ablative radiotherapy (SABR / SBRT)
A very precise form of radiotherapy that delivers a high dose to a small, well-defined tumour in a few sessions, used for selected early-stage or limited cancers.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- SABR delivers a high, very precise radiotherapy dose to a small, well-defined tumour in a few sessions (usually 1–8).
- It is used for selected cases, such as early-stage inoperable lung cancer and some limited secondary tumours, not for cancer in general.
- It can control the treated tumour well, but controlling one tumour is not the same as curing cancer everywhere, and it is not a cure-all.
- Side effects depend on the tumour's location, and SABR is only suitable for certain tumours; an MDT decides if it is right for you.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Delivers a high, focused dose that can control small, well-defined tumours effectively
Tumours that are large, poorly defined or widespread are generally not suitable for SABR.
Each session can take a while because of precise positioning and imaging, but the treatment is usually not painful and you go home afterwards.
Clear written advice on fatigue and site-specific symptoms to watch for.
Each session can take a while because of precise positioning and imaging, but the treatment is usually not painful...
Fatigue and site-specific effects (such as a cough after lung SABR) can develop. The team advises on managing...
The tumour's response is assessed, usually with scans. Early changes on scans can be hard to interpret and may...
Late effects can occasionally appear in the treated area. Ongoing scans monitor for tumour control and any new...
What is stereotactic ablative radiotherapy (SABR / SBRT)?
Stereotactic ablative radiotherapy (SABR), also called stereotactic body radiotherapy (SBRT), is a very precise form of external beam radiotherapy. It delivers a high dose of radiation to a small, well-defined target from many directions, in a small number of sessions, usually between one and eight, rather than the many sessions of a standard course.
Because the dose per session is high and tightly focused, SABR relies on very accurate planning, careful positioning, image guidance and often methods to account for movement such as breathing. It is used for selected situations, for example early-stage lung cancer in people who cannot have, or choose not to have, surgery, and for some limited secondary cancers (oligometastases).
SABR can be very effective at controlling the treated tumour, and for small early-stage lung cancers reported local control rates are high. But controlling the tumour that is treated is not the same as curing cancer everywhere, and SABR is only suitable for certain tumours that are small and well-defined. It is not a general substitute for surgery or for other radiotherapy, and it is not a cure-all.
As with all radiotherapy, the aim can be curative or to relieve symptoms, and there are real side effects that depend on where the tumour is. A good team is clear about why SABR has been chosen and what it can and cannot achieve.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
SABR vs a standard radiotherapy course
| Feature | What it means |
|---|---|
| Dose per session | SABR uses a high dose in few sessions; standard uses smaller daily doses over weeks |
| Suitability | SABR suits small, well-defined tumours; standard is used more broadly |
| Sessions | Usually 1–8 for SABR; often many more for a standard course |
| Accuracy needed | SABR needs very accurate planning, image guidance and motion control |
Fewer sessions does not mean lower risk; the high dose makes precision and patient selection essential.
Preparing for your treatment
- Attend detailed planning, usually a CT scan and sometimes an MRI or PET-CT, to map the tumour precisely.
- Expect assessment of whether your tumour is suitable; for lung SABR, lung function tests are usually done first.
- Follow any instructions about positioning aids and methods to manage movement, such as breathing techniques.
- Tell the team about all your medicines, supplements and other health conditions.
- Tell them if you are, or might be, pregnant.
- Plan for fatigue and for the longer time each session can take.
- Ask why SABR has been chosen for you and what the alternatives are, including surgery where relevant.
What happens
Planning is careful and detailed, using CT and sometimes MRI or PET-CT to define the small target and the nearby healthy tissues. The team designs a plan that focuses a high dose tightly on the tumour, which takes time to prepare and check.
For each session you lie very still, often with positioning aids, while the machine delivers radiation from many angles. Image guidance is used to confirm the target's position, and methods may be used to account for movement such as breathing. Each session can take longer than standard radiotherapy because of this precision, but the treatment itself is usually not painful.
Treatment is given in a small number of sessions, usually one to eight, sometimes on alternate days. You can normally go home afterwards. The number of sessions depends on the tumour's site and how close it is to sensitive structures.
Is this treatment right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Tumours that are large, poorly defined or widespread are generally not suitable for SABR.
- Tumours very close to critical central structures may be too risky for the high SABR dose.
- It is not a general substitute for surgery; for operable early-stage cancer, surgery may still be preferred.
- Pregnancy is usually a contraindication because radiation can harm the developing baby.
- Poor lung function or other factors may make even SABR unsuitable for lung tumours, which is why pre-treatment tests matter.
Delay or rearrange if…
- You are, or might be, pregnant, until this is resolved.
- You have an active infection or are acutely unwell and need stabilising first.
- Suitability assessment (such as lung function tests or staging scans) is incomplete.
- The tumour's position relative to critical structures needs further review before safe treatment.
Alternatives to discuss
- Surgery, where the tumour is operable and the person is fit enough.
- Standard or IMRT external beam radiotherapy where SABR is not suitable.
- Drug treatments such as chemotherapy, immunotherapy or targeted therapy, depending on the cancer.
- Active monitoring or supportive care where appropriate.
- Other local treatments (for example thermal ablation) in selected cases.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Delivers a high, focused dose that can control small, well-defined tumours effectively
- Needs only a few sessions, which can be more convenient than a long course
- An option for early-stage cancers when surgery is not possible or not wanted
- Can treat tumours that are difficult to reach surgically
- Spares more surrounding healthy tissue through high precision
- Usually given as an outpatient and does not make you radioactive
Risks & complications
- Tiredness (fatigue), which can build after treatment
- Site-specific effects depending on where the tumour is (for example a cough, breathlessness or chest-wall soreness for lung SABR)
- A skin reaction over the treated area in some cases
- Temporary worsening of symptoms before improvement
- Inflammation of nearby tissue (for example radiation pneumonitis in the lung), which may need treatment
- Rib or chest-wall pain, or a rib fracture, when treating tumours near the chest wall
- Longer-lasting effects on the treated area's function
- Need for further treatment if the tumour is not controlled or new disease appears
- Serious damage to nearby critical structures, especially for tumours close to central organs or large airways
- A second cancer in the treated area many years later
- Other serious site-specific complications, which the team should explain for your treatment
SABR delivers a high dose, so although sessions are few, careful patient selection and precision are essential. Tumours close to central structures (for example large airways or the gullet) carry higher risk and need extra caution. Ask your oncologist about the specific risks for your tumour's location, how likely they are, and what the realistic aim of treatment is.
Published figures to discuss
SABR can give high rates of control of the specific tumour treated, but this depends heavily on tumour type, size and site, and on patient selection. Local control is not the same as cure or survival, and figures from studies of selected, small, early-stage tumours may not apply to other situations. The single sourced figure below should be read with caution, and your oncologist should give figures relevant to your tumour. We have not stated survival percentages.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Control of the treated tumour (small early-stage lung cancer) | Reported around 90% or higher local control at about 3 years in selected series | This is control of the specific tumour treated in carefully selected small early-stage cancers, not a cure or survival guarantee; figures vary by study and do not apply to all situations. | SABR for early-stage NSCLC: dose-fractionation review — PMCncbi.nlm.nih.govPublished figure |
| Radiation pneumonitis after lung SABR | Usually uncommon to common; symptomatic rates are often quoted in the low single digits to teens depending on lung reserve and treated volume | New cough, fever or breathlessness weeks to months after treatment should be reported. | SABR for early-stage NSCLC: dose-fractionation review — PMCncbi.nlm.nih.govPublished figure |
| Chest-wall pain or rib fracture after peripheral lung SABR | Uncommon, higher when tumours are close to ribs | Dose constraints reduce risk but cannot remove it. | SABR for early-stage NSCLC: dose-fractionation review — PMCncbi.nlm.nih.govSource-linked context |
| Severe toxicity near central airways or critical organs | Uncommon but more likely for central or ultra-central tumours | Fraction number, dose and organ-at-risk constraints matter; SABR is not automatically safer because it is shorter. | SABR for early-stage NSCLC: dose-fractionation review — PMCncbi.nlm.nih.govSource-linked context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
SABR is given in a few sessions, but its effects build over the following weeks and months rather than straight away. Recovery is often easier than a long radiotherapy course, but fatigue and site-specific effects still occur, and some effects can appear later.
- Tiredness that can build in the weeks after treatment
- Site-specific symptoms such as a mild cough or chest-wall soreness after lung SABR
- Scan changes in the treated area that take time and expertise to interpret
- A gradual rather than immediate change in the tumour
Aftercare
- Follow the team's advice on managing fatigue and any site-specific symptoms.
- Report a new or worsening cough, breathlessness or fever after lung SABR, as inflammation can occur.
- Use any prescribed medicines, such as those for inflammation or pain, as directed.
- Attend follow-up scans so tumour control and any new disease are monitored.
- Pace yourself; light activity such as short walks can help recovery.
- Know who to contact for advice and what counts as an emergency.
- Suitability assessment (for example lung function tests) completed
- Understanding of why SABR was chosen over surgery or other radiotherapy
- Support arranged for fatigue and for longer session times
- Plan for follow-up scans noted
- Contact number for the radiotherapy team saved
- Clear list of symptoms to report urgently for your tumour site
⚠ Get urgent help if…
- New or worsening breathlessness, a persistent cough or coughing up blood after lung SABR.
- A high temperature, shivering or feeling very unwell.
- Severe or rapidly worsening pain in the treated area, including chest-wall pain.
- Difficulty swallowing or new chest pain when treating tumours near the gullet or central chest.
- Heavy or new bleeding.
- Severe or persistent symptoms specific to the treated area that the team has asked you to report.
- Any sudden, severe symptom should be treated as an emergency.
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
SABR can be very effective at controlling the specific tumour it treats, and for small, early-stage lung cancers reported local control rates are high. However, controlling the treated tumour is not the same as curing cancer throughout the body, and cancer can still appear elsewhere.
Response is assessed over weeks to months, usually with scans, and early scan changes can be difficult to interpret, sometimes needing expert review over time. As with all radiotherapy, no treatment guarantees a cure, and your team will explain the realistic aim for your situation.
How durable the result is depends on the tumour type, its size and site, and whether disease is present elsewhere. For suitable small early-stage tumours, long-term control of the treated area is often good, but ongoing monitoring is needed because new disease can develop and late effects can appear. SABR controls what it treats; it does not prevent cancer arising elsewhere.
Related tests, treatments or support
SABR is delivered using image guidance and motion-management techniques, and is sometimes used alongside or instead of surgery or other treatments depending on the situation. For more limited or widespread disease, drug treatments or standard radiotherapy may be more appropriate. The MDT decides whether SABR fits your overall plan.
Follow-up & long-term care
After SABR you are followed up with scans to assess tumour control and to watch for new disease and late effects, often over years. Early scan changes may need careful interpretation. You should have a contact for questions and know what symptoms to report urgently.
- Attend follow-up scans, which may continue for years, to monitor control and detect new disease.
- Report new or persistent symptoms in or near the treated area.
- Continue any recommended self-care for fatigue or site-specific effects.
- Keep a record of the treatment area and dose for future clinicians, as it can affect later treatment.
Repeat, follow-on and what comes next
- Further treatment may be needed if the treated tumour is not controlled or if new disease appears elsewhere.
- Re-treating the same area can be limited by the high dose already delivered.
- Early scan changes after SABR can be hard to interpret and may need repeat scans or biopsy.
- Late effects in the treated area may need their own management.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Clear written advice on fatigue and site-specific symptoms to watch for.
- A named contact and emergency instructions, especially for breathing symptoms after lung SABR.
- Planned follow-up scans to monitor tumour control and detect new disease.
- Expert interpretation of post-treatment scan changes over time.
- Coordination with the wider cancer team and your GP.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The complex planning and imaging SABR requires
- The number of sessions (usually 1–8) and the tumour site
- Any procedure for markers or motion management
- The delivery platform used (standard machine or a dedicated system)
- Consultant oncologist fees and physics/radiography input
- Follow-up scans and management of side effects
- Why SABR has been chosen and whether surgery or another technique is an option
- The number of sessions and the tumour site being treated
- What planning, imaging and motion-management are included
- What follow-up scans and management of side effects are included
- Whether MDT review and coordination with your cancer team are included
- What happens, and what it costs, if the tumour is not controlled or complications occur
On the NHS? SABR is available on the NHS for defined indications, such as early-stage inoperable lung cancer; people sometimes use private care for speed or choice, but suitability is the key issue and care should be coordinated with NHS cancer services.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Implying control of one tumour means the cancer is cured everywhere.
- Not explaining that SABR is only for selected tumours and is not a general substitute for surgery.
- Underplaying the higher risk when treating tumours near central structures.
- Quoting impressive control figures from selected studies as if they apply to everyone.
- Promoting a branded machine as automatically superior without evidence.
Marketing red flags
- Selling SABR or a branded system (for example by machine name) as a cure-all for cancer.
- Offering SABR for unsuitable or widespread disease without MDT support.
- Promising cure or guaranteed control.
- Quoting high control rates without explaining they apply only to selected small tumours and are not survival.
- Discouraging discussion of surgery, MDT review or a second opinion.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Why is SABR being recommended for me, and is surgery an option?
- What is the aim: to control the tumour, to attempt cure, or to relieve symptoms?
- How close is my tumour to sensitive structures, and what does that mean for my risk?
- How many sessions will I have, and how long will each take?
- How and when will you check whether it has worked, and how are scan changes interpreted?
- Who do I contact if I have side effects, and what counts as an emergency?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my treatment, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this treatment not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
How is SABR different from ordinary radiotherapy?
Is SABR suitable for any cancer?
Does SABR cure cancer?
Is SABR safer because it is fewer sessions?
Is a branded machine such as CyberKnife better?
Can I have SABR privately?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: Cancer Research UK — Stereotactic radiotherapy (SRT/SABR/SBRT) NICE NG122 — Lung cancer: diagnosis and management (SABR recommendations) NHS — Side effects of radiotherapy Macmillan Cancer Support — Radiotherapy side effects SABR for early-stage NSCLC: dose-fractionation review — PMC Royal College of Radiologists — Clinical oncology
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
Related guides: External beam radiotherapy · Intensity-modulated radiotherapy (IMRT) · Image-guided radiotherapy (IGRT) · Clinical oncology consultation · Brachytherapy (internal radiotherapy)