# Stereotactic radiosurgery (SRS)

Source: https://onco.cc/terms/stereotactic-radiosurgery/  
OnCo record `stereotactic-radiosurgery` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A single high dose of radiation delivered to a brain tumour or metastasis by beams converging from all sides, so the target gets a destructive dose while the surrounding brain gets little; no scalpel is involved despite the name. It treats metastases up to about 3-4 cm and has replaced whole-brain radiotherapy for limited disease because it spares cognition.

## Summary

Gamma Knife, CyberKnife and linac-based SRS treat brain metastases up to about 3-4 cm (or several at once) with local control above 80% and have replaced whole-brain radiotherapy for limited disease because they spare cognition (N0574, JLGK0901). Larger cavities after surgery get fractionated stereotactic radiotherapy in 3-5 sessions. Modern practice combines SRS with CNS-active drugs (osimertinib, tucatinib, T-DXd), and trials now test whether upfront SRS can be deferred when such drugs are available.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: SRS; radiosurgery; Gamma Knife; gamma knife; fractionated stereotactic radiotherapy

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Radiosurgery
- Wikipedia: https://en.wikipedia.org/wiki/Radiosurgery

## Connected records

- terms: [Brain metastases (intracranial disease)](https://onco.cc/terms/brain-metastases/), [Graded Prognostic Assessment (GPA) for brain metastases](https://onco.cc/terms/graded-prognostic-assessment/), [Palliation in advanced triple-negative breast cancer: brain, bone, pleura, skin and end of life](https://onco.cc/terms/tnbc-symptom-control-palliation/), [Stereotactic body radiotherapy (SBRT / SABR)](https://onco.cc/terms/sbrt-term/), [Whole-brain radiotherapy (WBRT)](https://onco.cc/terms/wbrt/)
- fronts: [Radiation Therapy](https://onco.cc/fronts/radiation/)
- technologies: [CyberKnife robotic radiosurgery](https://onco.cc/technologies/cyberknife/), [Gamma Knife](https://onco.cc/technologies/gamma-knife/), [SBRT / SABR (stereotactic radiotherapy)](https://onco.cc/technologies/sbrt/), [Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/), [ZAP-X gyroscopic radiosurgery](https://onco.cc/technologies/zap-x/)
- cancers: [Brain metastases (secondary brain tumours)](https://onco.cc/cancers/secondary-brain-tumours/), [HER2-positive breast cancer with brain metastases](https://onco.cc/cancers/her2-positive-breast-brain-metastases/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Meningioma](https://onco.cc/cancers/meningioma/), [Metastatic cancer (cancer that has spread)](https://onco.cc/cancers/metastatic-cancer/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/), [Vestibular schwannoma (acoustic neuroma)](https://onco.cc/cancers/vestibular-schwannoma/)
- key papers: [Prophylactic cranial irradiation for patients with small-cell lung cancer in complete remission](https://onco.cc/key-papers/paper-auperin-prophylactic-cranial-irradiation-sclc-nejm-1999/)
- ideas: [Measure brain metastasis prevention as a primary endpoint, not as a secondary one](https://onco.cc/ideas/idea-lung-brain-metastasis-prevention-as-a-primary-endpoint/)
- trials: [Alliance N0574 (NCCTG N0574)](https://onco.cc/trials/alliance-n0574/)

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