Can SBRT be used if surgery is not an option?

Yes, and this is one of its most important applications. SBRT was developed specifically as an ablative alternative for patients who cannot safely undergo surgery, such as those with severe lung disease, heart failure, advanced age or other medical conditions that make general anaesthesia and surgical recovery unsafe.

How many SBRT sessions will I need?

The number of sessions (fractions) depends on the tumour type and location. The radiation oncologist will determine the appropriate number of fractions based on the tumour's biology, size and proximity to critical structures. ( usually 3 to 8)

How long does each SBRT session usually take?( same changes)

Each SBRT session typically takes 30 to 90 minutes in the treatment room though the actual radiation delivery is only 10 to 30 minutes of this. The rest of the time is spent on positioning, image verification and final quality checks before treatment begins.

Can I return to my normal activities after SBRT?

Most patients can return to normal daily activities, including light work and household tasks, the same day or the day after each session. SBRT does not require the recovery period associated with surgery or the cumulative fatigue that builds over a prolonged conventional radiotherapy course.

Will I need to stay in the hospital during SBRT treatment?

SBRT is an outpatient treatment and no hospital admission or overnight stay is required. Patients attend the hospital only for each treatment session, which lasts one to two hours and then return home.

Does SBRT hurt during the treatment?

Some patients experience mild discomfort from the immobilisation device or from lying in a fixed position for 30 to 45 minutes but the radiation beam itself causes no pain.

How soon can I expect results after completing SBRT?

Tumour response to SBRT is not immediate. The tumour may continue to appear on imaging for several months after treatment as the radiation-damaged cells are gradually broken down and absorbed by the body. Follow-up imaging is typically performed at three to six months after SBRT to assess the initial response.

Can cancer come back after SBRT?

Local recurrence (the tumour growing back at the treated site) can occur but is uncommon after SBRT when the treatment is delivered correctly and the appropriate patient and tumour criteria are met. However, new tumours can develop at other sites in the body (distant recurrence or metastasis) independently of the locally treated tumour, which is why ongoing surveillance imaging is important.

Will I need follow-up scans after SBRT?

Regular follow-up imaging is an essential part of care after SBRT. CT scans, MRI scans or PET-CT scans are performed at defined intervals (typically every three to six months for the first two years and then annually) to monitor the treated tumour site for response, assess for local recurrence and look for new disease at other sites.

Can SBRT be combined with chemotherapy or other cancer treatments?

Yes SBRT is frequently combined with systemic treatments including chemotherapy, immunotherapy and targeted therapy, depending on the tumour type and treatment goals. The sequencing and combination of SBRT with other treatments is determined by the multidisciplinary oncology team.

SBRT: How High-Precision Radiation Is Used for Selected Tumours

Medically Reviewed By Dr. Resham Srivastava, DNB (Radiation Oncology) , MD (Radiation Oncology) , M.B.B.S, Associate Director - Cancer Care

Updated on: Sep 21, 2026
Published on: Sep 21, 2026

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Radiation therapy has been part of cancer treatment for over a century but the way it is delivered has changed dramatically. Traditional radiotherapy required daily sessions over five to seven weeks, delivering relatively low doses per session to minimise harm to surrounding healthy tissue. Stereotactic body radiation therapy (SBRT) also known as stereotactic ablative radiotherapy (SABR) delivers very high doses of radiation with extreme precision in just one to five sessions, targeting the tumour so accurately that surrounding tissue receives comparatively little radiation.

What Is Stereotactic Body Radiation Therapy (SBRT)?

SBRT is a non-invasive radiation technique that uses a large number of precisely aimed beams, directed from multiple angles around the body, to converge on a tumour target with millimetre-level accuracy.

SBRT is distinct from conventional radiotherapy in both its dose per session and total number of sessions. Conventional radiotherapy typically delivers 1.8 to 2 Gray (Gy) per fraction over 25 to 35 fractions. Whereas SBRT delivers 6 to 20 Gy or more per fraction over 1 to 5 fractions with the total biologically effective dose substantially higher than what is achievable with conventional fractionation. This high dose per fraction is what gives SBRT its tumour-ablative power.

How SBRT Works: The Science Behind the Precision

SBRT's precision depends on three interconnected elements: accurate tumour localisation, precise patient positioning and real time motion management.

Before treatment begins the patient undergoes a planning CT scan, often combined with MRI or PET-CT (in the exact position they will maintain during treatment) that creates a detailed 3D map of the tumour and nearby organs, allowing doctors to target the tumour while protecting healthy tissue.

During treatment, image guidance systems (IGRT) verify the tumour's position immediately before and sometimes during each session. Some SBRT systems such as the CyberKnife use real-time tumour tracking with robotic beam delivery that continuously adjusts the beam direction as the tumour moves with breathing. Other systems use respiratory gating, in which the radiation beam is switched on only during a specific phase of the breathing cycle.

Tumours and Cancers Commonly Treated With SBRT

SBRT has established clinical evidence for the following tumour types and indications.

Early-stage non-small cell lung cancer (NSCLC): SBRT is now the standard of care for medically inoperable Stage I NSCLC and for operable patients who prefer to avoid surgery.
Liver tumours: Primary hepatocellular carcinoma (HCC) and liver metastases from colorectal, breast and other cancers can be treated with SBRT when surgical resection or ablation is not feasible.
Spine metastases: SBRT delivers high-dose, precisely targeted radiation to spinal metastases while sparing the adjacent spinal cord.
Prostate cancer: SBRT delivers the full course of prostate radiotherapy in five fractions rather than 20 to 39 fractions with conventional techniques.
Renal cell carcinoma: SBRT is an effective ablative treatment for small renal masses in patients who are not surgical candidates.

SBRT vs Conventional Radiation Therapy

The differences between SBRT and conventional radiotherapy are not simply technical. They have fundamentally different treatment strategies.

Total sessions: Conventional radiotherapy delivers 25 to 35 sessions over five to seven weeks whereas SBRT delivers 1 to 5 sessions over one to two weeks
Dose per session: Conventional radiotherapy: 1.8 to 2 Gy per session. SBRT: 6 to 20 Gy or more per session
Required technology: Conventional radiotherapy can be delivered on standard linear accelerators. SBRT requires advanced image guidance (IGRT), motion management and high-precision treatment planning.
Tumour size and complexity: Conventional radiotherapy is used for a broader range of tumour sizes and locations. SBRT is limited to small, well-defined tumours (typically up to 5 to 6 centimetres) with no nearby critical structure that cannot be spared.

Who Is a Good Candidate for SBRT?

SBRT is most appropriate for patients with the following characteristics.

Small, well-defined tumours (approximately 5 to 6 centimetres) in diameter clearly visible on imaging.
SBRT is most commonly used for one to three tumour sites (oligometastatic disease), where ablation of all sites is clinically feasible.
For patients who cannot undergo surgery SBRT offers a non-invasive ablative alternative that does not require anaesthesia or a hospital stay.
The high-dose zone should not include adjacent critical structures.

What to Expect During SBRT Treatment

The SBRT process begins well before the first treatment session:

The patient undergoes a planning CT scan that is often combined with MRI or 4D-CT, in the exact position they will maintain during treatment. Immobilisation devices such as a body frame or vacuum bag are custom-fitted to ensure reproducible positioning at every session. The radiation oncologist and medical physicist then design the treatment plan.

Each SBRT treatment session typically lasts 30 to 90 minutes. (30 to 45 minutes) However the actual radiation delivery is only 5 to 15 minutes. The patient lies still on the treatment table and the machine rotates around them. The patient feels no pain, sensation or noise from the radiation itself. Sessions are typically spaced at least 24 to 48 hours apart to allow normal tissue to recover between fractions.

Benefits and Advantages of SBRT

High local control rates: For appropriate tumours and patients, SBRT achieves local tumour control rates comparable to or exceeding those of surgery particularly for early-stage lung cancer and liver tumours.
Short treatment duration: The one to five session schedule minimises disruption to daily life, work and family commitments
Non-invasive: SBRT requires no surgical incision, no anaesthesia and no recovery period
Applicable to patients unfit for surgery: SBRT provides an effective ablative option for patients who cannot safely undergo surgery, expanding treatment options for elderly patients & those with significant comorbidities.

Possible Side Effects and Risks

SBRT is generally well tolerated, but side effects can occur in the weeks and months after treatment.

Fatigue
Site-specific side effects like radiation pneumonitis (Lung SBRT), radiation-induced liver injury (Liver SBRT) and vertebral fracture at the treated level (Spine SBRT).
Late effects like radiation fibrosis of the treated region or, very rarely, radiation-induced secondary malignancy.

Conclusion: Is SBRT Right for You?

SBRT is not appropriate for every cancer or every patient, but for the right clinical situation it offers a highly effective, non-invasive and time-efficient treatment that can achieve results comparable to surgery in selected tumour types. It is now a standard treatment option for early-stage lung cancer, liver tumours, spine metastases and prostate cancers.

Whether SBRT is appropriate for a specific patient depends on the tumour type, size, location, the number of tumour sites, the proximity of critical structures and the patient's overall health. These decisions are made by a multidisciplinary team. Consultation with a radiation oncologist can help determine whether SBRT is the right treatment option for you.

FAQs

Can SBRT be used if surgery is not an option?
Yes, and this is one of its most important applications. SBRT was developed specifically as an ablative alternative for patients who cannot safely undergo surgery, such as those with severe lung disease, heart failure, advanced age or other medical conditions that make general anaesthesia and surgical recovery unsafe.
How many SBRT sessions will I need?
The number of sessions (fractions) depends on the tumour type and location. The radiation oncologist will determine the appropriate number of fractions based on the tumour's biology, size and proximity to critical structures. ( usually 3 to 8)
How long does each SBRT session usually take?( same changes)
Each SBRT session typically takes 30 to 90 minutes in the treatment room though the actual radiation delivery is only 10 to 30 minutes of this. The rest of the time is spent on positioning, image verification and final quality checks before treatment begins.
Can I return to my normal activities after SBRT?
Most patients can return to normal daily activities, including light work and household tasks, the same day or the day after each session. SBRT does not require the recovery period associated with surgery or the cumulative fatigue that builds over a prolonged conventional radiotherapy course.
Will I need to stay in the hospital during SBRT treatment?
SBRT is an outpatient treatment and no hospital admission or overnight stay is required. Patients attend the hospital only for each treatment session, which lasts one to two hours and then return home.
Does SBRT hurt during the treatment?
Some patients experience mild discomfort from the immobilisation device or from lying in a fixed position for 30 to 45 minutes but the radiation beam itself causes no pain.
How soon can I expect results after completing SBRT?
Tumour response to SBRT is not immediate. The tumour may continue to appear on imaging for several months after treatment as the radiation-damaged cells are gradually broken down and absorbed by the body. Follow-up imaging is typically performed at three to six months after SBRT to assess the initial response.
Can cancer come back after SBRT?
Local recurrence (the tumour growing back at the treated site) can occur but is uncommon after SBRT when the treatment is delivered correctly and the appropriate patient and tumour criteria are met. However, new tumours can develop at other sites in the body (distant recurrence or metastasis) independently of the locally treated tumour, which is why ongoing surveillance imaging is important.
Will I need follow-up scans after SBRT?
Regular follow-up imaging is an essential part of care after SBRT. CT scans, MRI scans or PET-CT scans are performed at defined intervals (typically every three to six months for the first two years and then annually) to monitor the treated tumour site for response, assess for local recurrence and look for new disease at other sites.
Can SBRT be combined with chemotherapy or other cancer treatments?
Yes SBRT is frequently combined with systemic treatments including chemotherapy, immunotherapy and targeted therapy, depending on the tumour type and treatment goals. The sequencing and combination of SBRT with other treatments is determined by the multidisciplinary oncology team.

References

1. Timmerman R, Paulus R, Galvin J, et al. Stereotactic body radiation therapy for inoperable early stage lung cancer. JAMA. 2010;303(11):1070–6. https://doi.org/10.1001/jama.2010.261

2. Palma DA, Olson R, Harrow S, et al. Stereotactic ablative radiotherapy versus standard of care palliative treatment in patients with oligometastatic cancers (SABR-COMET): a randomised, phase 2, open-label trial. Lancet. 2019;393(10185):2051–8. https://doi.org/10.1016/S0140-6736(18)32487-5

3. Brand DH, Tree AC, Ostler P, et al. Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-B): acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol. 2019;20(11):1531–43. https://doi.org/10.1016/S1470-2045(19)30569-8

4. Bujold A, Massey CA, Kim JJ, et al. Sequential phase I and II trials of stereotactic body radiotherapy for locally advanced hepatocellular carcinoma. J Clin Oncol. 2013;31(13):1631–9. https://doi.org/10.1200/JCO.2012.44.1659

5. Sahgal A, Myrehaug SD, Siva S, et al. Stereotactic body radiotherapy versus conventional external beam radiotherapy in patients with painful spinal metastases: an open-label, multicentre, randomised, controlled, phase 2/3 trial. Lancet Oncol. 2021;22(7):1023–33. https://doi.org/10.1016/S1470-2045(21)00196-0