Cerebellar metastases radiosurgery

• Patterns of Recurrence After Postoperative Stereotactic Radiotherapy for Brain Metastases
• Cerebellar re-irradiation after whole brain radiotherapy significant symptom relief with minimal toxicity in metastatic brain patients
• Association between tumor location and toxicity outcomes after stereotactic radiosurgery for brain metastases
• Experience of Gamma Knife radiosurgery for treatment of brain metastases in pregnancy with literature review
• Audit of Presentation, Primary Site, and Pattern of Treatment in 778 Indian Patients with Brain Metastasis in 15 Years (2007-2022)
• Clinical and molecular characteristics of patients with brain metastasis secondary to pancreatic ductal adenocarcinoma
• Is two-staged gamma knife surgery a reasonable management option for very large cerebellar metastases? A case series of three patients
• Twenty-Month Regression Following Concurrent Conventional Whole-Brain Irradiation and Chemoimmunotherapy for 3.8 cm Cerebellar Metastasis From Small Cell Lung Cancer

• Cerebellar metastases represent 20–30% of all brain metastases.
• Frequent primaries:
  • Lung
  • Breast
  • Melanoma
  • Renal cell carcinoma
• Critical concerns:
  • Brainstem compression
  • Fourth ventricle involvement
  • Risk of obstructive hydrocephalus or herniation

• Lesion size <3–4 cm or volume <10–15 cc
• Oligometastatic disease (≤4 lesions)
• Good functional status (KPS ≥70)
• Controlled systemic disease
• Life expectancy >3–6 months

• Minimally invasive
• High local control (85–95% at 6–12 months)
• Outpatient or short-stay procedure
• Defers or avoids WBRT
• Preserves neurocognition
• Often avoids surgical resection

• Technologies:
  • Gamma Knife (GKRS)
  • CyberKnife
  • LINAC-based SRS
  • Hypofractionated SRS (hfSRS)
• Dose example:
  • 18–24 Gy in 1 fraction (adapted to size/location)
• Frameless or frame-based delivery

• Complications:
  • Radiation necrosis (5–15%)
  • Cerebellar edema → treat with corticosteroids
• Lesions near brainstem → consider hypofractionation
• Surveillance:
  • MRI brain with contrast:
    • 1st control at 2–3 months
    • Then every 2–3 months

• Retrospective studies show:
  • High local control
  • Comparable to surgery for small, asymptomatic lesions
• Preferred approach for large/symptomatic lesions:
  • Surgical resection + adjuvant SRS to cavity

Upfront Frameless Hypofractionated Gamma Knife Radiosurgery