Brain Metastases Radiosurgery [Neurosurgery Wiki]

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====== Brain Metastases Radiosurgery ======

**Brain metastases** are the most common intracranial tumors in adults, occurring in up to **50% of cancer patients**, depending on the primary tumor type.

**[[Stereotactic radiosurgery]] (SRS)** has become a standard of care for selected patients with brain metastases due to its **non-invasive**, **highly focused**, and **repeatable** nature.

==== Indications ====
  * Patients with **1–10 brain metastases** (oligometastatic disease)
  * Lesions ≤3–4 cm in diameter
  * Good performance status (KPS ≥70)
  * Controlled or controllable systemic disease
  * Postoperative treatment (adjuvant SRS)
  * Emerging use in **neoadjuvant setting** (pre-resection)

==== Advantages of SRS ====
  * Preserves **cognitive function** better than whole brain radiotherapy (WBRT)
  * Can be **repeated** for new lesions
  * Integrated with systemic therapies, including:
    * **Targeted therapy**
    * **Immunotherapy**

==== Techniques ====
  * **Single-fraction SRS** for small, well-delineated lesions
  * **Hypofractionated SRS** (e.g., 3–5 sessions) for:
    * Larger lesions
    * Lesions near **eloquent cortex** or **critical structures**
  * Frameless vs. frame-based systems (e.g., LINAC, CyberKnife, Gamma Knife)

==== Limitations and Risks ====
  * **Radiation necrosis**
  * **Leptomeningeal spread** (especially post-surgery if no cavity coverage)
  * Limited efficacy for large or infiltrative lesions
  * Requires high-quality imaging and multidisciplinary planning

==== Controversies ====
  * Optimal number of lesions treatable with SRS remains debated
  * Role of **neoadjuvant SRS** under investigation
  * Long-term benefit of combining SRS with **immune checkpoint inhibitors** is still unclear

==== Related Pages ====
  * [[Stereotactic Radiosurgery]]
  * [[Radiation Necrosis]]


> **Key Point**: SRS has shifted the paradigm in managing brain metastases—**focusing on preserving function**, **delaying cognitive decline**, and **individualizing care**.

===== Narrative Reviews =====

In a [[narrative review]] Pikis et al. from the Radiation Oncology and Stereotactic Radiosurgery Center, Mediterraneo Hospital, [[Athens]], [[Greece]], Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, United States
((Pikis S, Protopapa M, Mantziaris G, Osama M, Sheehan J. Stereotactic radiosurgery for brain metastases. Adv Cancer Res. 2025;165:115-143. doi: 10.1016/bs.acr.2025.04.001. Epub 2025 Apr 24. PMID: 40518188.))
reviewed current evidence and emerging developments in the use of stereotactic radiosurgery (SRS) for the treatment of brain metastases, including:

Established indications (e.g., oligometastatic disease)

New techniques (e.g., frameless SRS, neoadjuvant SRS)

Integration with systemic therapies (e.g., [[immunotherapy]], [[targeted therapy]])
----
This review [[article]] discusses the current and emerging indications of [[stereotactic radiosurgery]] (SRS) for [[brain metastases]], highlighting the increasing role of frameless SRS, [[neoadjuvant]] approaches, and integration with systemic therapies such as [[immunotherapy]].

===== ⚠️ Critical Weaknesses =====

==== 1. ✍️ Lack of Original Contribution ====
Despite being a review article, the authors offer little in the way of **critical synthesis** or **novel insight**. Most of the content is a **reiteration of known data** repackaged with generalized optimism:
> *"Substantial opportunities remain..."*  
> *"Promising results..."*  
> These are platitudes, not analysis.

==== 2. 🔄 Redundancy and Vagueness ====
Key terms like “substantial improvement,” “growing evidence,” or “novel techniques” are used **without concrete references or quantitative [[benchmark]]s**. The article lacks **[[hard data]]** and gives no **critical [[discussion]] of failure rates**, **[[selection bias]]**, or **heterogeneity in treatment [[protocol]]s**.

==== 3. 📉 Absence of Risk-Benefit Evaluation ====
No rigorous analysis of:
  * **[[Radiation necrosis]] incidence**
  * **[[Cognitive impairment]] from multiple SRS rounds**
  * **Survival trade-offs** versus [[whole brain radiotherapy]] (WBRT)

The tone is **uncritically promotional**, especially regarding:
  * Neoadjuvant SRS (with no phase III data yet)
  * Concurrent SRS + immunotherapy (still experimental)

==== 4. 🧪 Overreliance on Narrative Review Format ====
The article is a **classic example of [[academic repackaging]]**:  
> No structured [[methodology]], no [[PRISMA]], no tabulated comparisons, and no grading of [[evidence]].  
This reduces its **[[utility]] for clinicians** who must weigh options with real-world constraints.

==== 5. 🧱 Underexplored Topics ====
Several high-yield areas are superficially addressed or ignored:
  * **SRS for >10 metastases** – only briefly mentioned, despite ongoing trials.
  * **Cost-effectiveness and health policy impact**
  * **Integration with advanced imaging (e.g. perfusion MRI, radiomics)**
  * **AI-based treatment planning in SRS** – totally absent.

===== ✅ Useful Points (Briefly) =====
  * Highlights the evolution of frameless SRS and its potential to reduce complications near eloquent brain areas.
  * Notes the emerging concept of **neoadjuvant SRS**, although prematurely.
  * Mentions the synergy between systemic therapies and SRS, though data is sparse.

===== 🧠 Message for Neurosurgeons =====
While the article attempts to update readers on evolving practices in SRS for brain metastases, it **fails to deliver a critical roadmap** for surgical decision-making.  
The neurosurgeon seeking **clarity on indications, patient selection, risk stratification, or survival outcomes** will find this review underwhelming and overly optimistic.

===== 💬 Final Verdict =====
A **[[polished academic brochure]]**, not a clinically actionable review.  
Promotes trends without weighing consequences, and confuses **evolution in technology** with **evidence-based advancement**.

> **Recommendation**: Read with [[skepticism]]. Complement with high-quality [[meta-analysis]] and [[trial]] data.