STEREOTACTIC RADIOSURGERY
AND RADIOTHERAPY FOR BRAIN CANCER
SRS treats brain tumours with the precision of surgery โ without a scalpel. Single or few-fraction high-dose radiation delivered to within 1 mm of the target, sparing surrounding brain with remarkable accuracy.
analyticsAt a Glance
- check_circleSRS: 1โ5 fractions โ 85โ95% local control for brain metastases at 1 year
- check_circleNo surgery, no hospital admission โ outpatient or 1-day procedure
- check_circleGamma Knife, CyberKnife, and linac-based SRS available in India and China
- check_circleSRS cost in India: $3,000โ$6,000 vs $15,000โ$35,000 in the USA
What Is Stereotactic Radiosurgery?
Stereotactic radiosurgery (SRS) is not surgery โ it uses dozens of precisely aimed radiation beams converging on a tumour target, each beam individually too weak to harm brain tissue it passes through, but collectively delivering a tumour-lethal dose at their intersection point.
โSRS does not cut the tumour out โ it destroys it from outside, from multiple beam angles simultaneously, with sub-millimetre accuracy. The tumour cannot be rebuilt; the normal brain the beams pass through is largely unaffected.โ
How SRS Achieves Precision
Stereotactic frame or frameless mask immobilises the head. MRI-CT image fusion maps the tumour with sub-millimetre accuracy. Thousands of possible beam angles are planned computationally to maximise tumour dose while minimising dose to brainstem, optic chiasm, cochlea, and eloquent cortex. Real-time image guidance verifies position before each beam delivery.
SRS vs FSRT: When to Fractionate
Single-fraction SRS: best for lesions โค3 cm, well away from critical structures (brainstem, optic chiasm). Fractionated SRS/FSRT (3โ5 fractions): preferred for tumours >3 cm, adjacent to brainstem or optic apparatus, or re-irradiation cases. Fractionation exploits normal tissue repair between fractions while maintaining tumour ablation.
SRS Platforms: Gamma Knife vs CyberKnife vs Linac-Based SRS
Multiple platforms deliver SRS โ the oncological outcomes are equivalent when delivered by experienced teams to the same dose specifications. Platform choice is determined by centre availability, not by superiority of any system.
| Platform | How It Works | Best For | Limitations |
|---|---|---|---|
| Gamma Knife (Elekta) | 192 cobalt-60 sources converge on the target; frameless Gamma Knife Icon allows CBCT image guidance | Intracranial targets only; brain mets, meningioma, AVM, trigeminal neuralgia; highest evidence base for small brain targets | Cannot treat extracranial targets; frameless version required for fractionation |
| CyberKnife (Accuray) | Robotic linac arm moves to 100+ positions, tracking tumour with real-time X-ray image guidance throughout treatment | Intracranial and extracranial targets; spine SBRT; frameless; real-time tracking compensates for patient motion | Longer treatment time per session; higher complexity for small brain targets vs Gamma Knife |
| Linac-based SRS (TrueBeam, Versa HD, Edge) | Standard linear accelerator with stereotactic cone or MLC collimation, CBCT image guidance, and 6DOF couch | Both intracranial and extracranial; FSRT; cost-effective vs dedicated systems; wider availability | Requires specific SRS-dedicated hardware and software; quality dependent on centre expertise and SRS-specific programme |
SRS / FSRT by Brain Tumour Indication
Indication, dose, fractionation, and outcomes vary significantly by brain tumour type โ this table summarises the standard approach for each.
| Indication | Approach | Typical Dose | Local Control Rate |
|---|---|---|---|
| Brain metastases (1โ3 lesions, โค3 cm) | Single-fraction SRS | 18โ24 Gy ร 1 fx | 85โ95% at 1 year |
| Brain metastases (3โ4 cm or brainstem adjacent) | FSRT (3โ5 fractions) | 25โ30 Gy / 5 fx or 27 Gy / 3 fx | 80โ90% at 1 year |
| Brain metastases (>4 lesions โ multiple SRS) | Multiple-target SRS in single session | 18โ22 Gy ร 1 fx per lesion | 80โ90% per lesion at 1 year |
| Meningioma (WHO Grade 1, residual/recurrent) | SRS or FSRT depending on size and location | 12โ14 Gy ร 1 fx or 50 Gy / 25 fx (IMRT) for large | 90โ95% progression-free at 5 years |
| Acoustic neuroma (vestibular schwannoma) | Single-fraction SRS (Gamma Knife preferred) | 12โ13 Gy ร 1 fx | 95%+ tumour control at 5 years |
| Recurrent GBM (small focal recurrence) | FSRT (5 fractions) or SRS | 25โ30 Gy / 5 fx | 50โ70% local control at 1 year |
| AVM (arteriovenous malformation) | Single-fraction SRS | 20โ25 Gy ร 1 fx (obliteration dose) | 70โ85% obliteration at 3 years |
| Trigeminal neuralgia | Single-fraction SRS to trigeminal root entry zone | 70โ90 Gy ร 1 fx (maximum point dose) | 70โ80% initial pain relief |
SRS vs Whole-Brain Radiotherapy (WBRT) for Brain Metastases
The field has shifted dramatically toward SRS over WBRT โ driven by evidence that WBRT causes neurocognitive toxicity without survival benefit over SRS for limited brain metastases.
SRS Preferred
- 1โ10 brain metastases (growing evidence supports SRS for >4)Multiple RCTs show equivalent or better OS vs WBRT with superior neurocognitive preservation
- Neurocognitive function preservationWBRT causes measurable memory and cognitive decline in 40โ60% of patients at 6 months; SRS avoids hippocampal irradiation
- Controlled systemic disease with long expected survivalPatients expected to survive >6 months derive greatest neurocognitive benefit from SRS over WBRT
- Targetable driver mutation (EGFR, ALK, HER2, BRAF)Systemic targeted therapy + SRS may defer or avoid WBRT entirely โ preserving neurocognitive function while achieving local control
WBRT May Be Preferred
- Diffuse leptomeningeal metastasesSRS cannot treat microscopic leptomeningeal disease โ WBRT covers the entire cranial compartment
- >10 small lesions (selected cases)Very high burden not amenable to practical multi-lesion SRS at some centres
- Poor performance status with short life expectancy5 fractions of WBRT (20 Gy) is a simple, low-toxicity palliative approach where SRS precision is not required
- Hippocampal avoidance WBRTModern WBRT with hippocampal avoidance (HA-WBRT) reduces neurocognitive decline vs standard WBRT โ now preferred over standard WBRT when whole-brain treatment is needed
SRS for Brain Cancer: Key Outcome Benchmarks
- 85โ95%Brain Met Local Control at 1 Year (SRS)Across histologies โ highest for breast and NSCLC; lower for melanoma without immunotherapy
- 95%+Acoustic Neuroma Control at 5 Years (Gamma Knife)SRS is the primary treatment for acoustic neuromas โค3 cm โ equivalent to surgery with lower morbidity
- 50โ70%Local Control โ Recurrent GBM re-SRSFor small-volume, focal recurrence at โฅ6 months from prior RT
- $3โ6KSRS Cost in India (1โ3 Brain Mets)vs $15,000โ$35,000 in the USA โ 70โ80% cost saving
Related Brain Cancer Treatment Resources
More guides on brain tumour radiation and treatment options.
Frequently Asked Questions
SRS and FSRT for Brain Cancer
Is SRS as effective as surgery for brain metastases?
For most brain metastases โค3 cm, SRS achieves equivalent local control to surgical resection โ with RCT-level evidence demonstrating comparable 1-year local control rates (85โ95%) between the two approaches. SRS avoids general anaesthesia, craniotomy risk, and hospital admission โ making it strongly preferred for patients with limited brain disease and controlled or manageable systemic disease. Surgery is preferred when tissue diagnosis is needed, when the lesion causes significant mass effect and immediate decompression is required, or when the lesion is in an accessible location and the patient is an excellent surgical candidate.
Can SRS treat multiple brain metastases?
Yes. SRS for multiple brain metastases (up to 10 or more) is now widely practised. Multiple studies have demonstrated that SRS for 5โ10 or even more small brain metastases achieves equivalent OS to SRS for 1โ4, without the neurocognitive toxicity of whole-brain radiotherapy. At experienced centres, 10+ lesions can be treated in a single SRS session using multi-target planning on Gamma Knife or CyberKnife platforms. The practical limit is set by total intracranial disease burden rather than number alone.
Is SRS available in India and China, and is it as good?
Yes โ Gamma Knife, CyberKnife, and linac-based SRS are available at multiple major cancer centres in India (Fortis, Apollo, Manipal, HCG, AIIMS) and China (Tiantan, Xuanwu, Huashan, PUMCH). Experienced neuro-radiation oncologists at these centres trained in the same SRS protocols as Western centres, using identical planning software and treatment systems. Outcomes data from Indian and Chinese high-volume SRS programmes are equivalent to international benchmarks. Cost at Indian centres is $3,000โ$6,000 for a single-session SRS vs $15,000โ$35,000 in the USA.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination โ travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Exploring SRS for a Brain Tumour?
Upload your brain MRI and pathology. CancerFax will assess SRS eligibility, recommend the most appropriate platform, and connect you with experienced neuro-radiation oncologists in India or China.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.