Prospective Study of Keyhole Craniotomy and Cs-131 Brachytherapy for Brain Oligometastases
Overview
This prospective study evaluated the combination of minimally invasive keyhole craniotomy (MIKC) and Cesium-131 (Cs-131) stereotactic brachytherapy (SBT) in 21 patients with newly diagnosed brain oligometastases. The treatment demonstrated effective local tumor control, low toxicity, and favorable functional and quality of life outcomes over a two-year follow-up.
Background
Metastatic brain tumors are the most common intracranial tumors, often arising from lung, breast, kidney, gastrointestinal, and skin cancers. Standard treatments include surgical resection followed by radiation therapy or stereotactic radiosurgery, but whole brain radiotherapy is associated with neurocognitive decline. Stereotactic brachytherapy using Cs-131 offers targeted radiation with a shorter half-life and reduced radiation necrosis compared to Iodine-125. Minimally invasive keyhole craniotomy reduces surgical trauma and facilitates access to difficult tumor locations. Combining these modalities may improve local control and patient outcomes in brain oligometastases.
Data Highlights
Parameter
Value/Description
Number of patients
21 adults with newly diagnosed brain metastases
Follow-up duration
Up to 2 years, with assessments every 2 months
Inclusion criteria
1–6 newly diagnosed tumors, KPS ≥ 60, ECOG ≤ 2
Exclusion criteria
More than 6 lesions, prior radiosurgery or whole brain radiation, KPS < 60, ECOG > 3
Cs-131 seed activity
3–5 mCi per seed
Assessment tools
RANO-BM criteria, MRI, KPS, ECOG, FACT-Br, MMSE
Key Findings
Combination of MIKC and Cs-131 SBT provided effective local tumor control in brain oligometastases.
Cs-131 brachytherapy was associated with lower rates of radiation necrosis compared to historical I-125 data.
Functional status and quality of life were maintained or improved post-treatment as measured by KPS, ECOG, and FACT-Br scores.
Neurocognitive function remained stable based on MMSE assessments during follow-up.
Minimally invasive keyhole craniotomy reduced surgical trauma and facilitated access to tumors in challenging locations.
The approach allowed timely initiation of systemic therapy due to rapid dose delivery from Cs-131’s short half-life.
Clinical Implications
The combined use of minimally invasive keyhole craniotomy and Cs-131 stereotactic brachytherapy offers a promising treatment modality for patients with newly diagnosed brain oligometastases, especially for lesions not amenable to conventional radiosurgery. This approach may reduce radiation necrosis risk, preserve neurocognitive function, and improve quality of life while enabling rapid postoperative recovery and systemic therapy initiation.
Conclusion
This prospective investigation supports the safety and efficacy of combining MIKC with Cs-131 brachytherapy for local control of brain oligometastases, demonstrating favorable functional outcomes and low toxicity. Further larger studies are warranted to confirm these findings and optimize treatment protocols.
References
Nayak et al. 2012 -- Epidemiology of Brain Metastases
Sperduto et al. 2017 -- Treatment Modalities for Brain Metastases
Chang et al. 2009 -- Neurocognitive Effects of WBRT vs. SRS
Minniti et al. 2014 -- Hypofractionated Stereotactic Radiotherapy
Patel et al. 2012 -- Iodine-125 Brachytherapy for Brain Tumors
Wernicke et al. 2014 -- Cs-131 Brachytherapy in Brain Metastases
Wernicke et al. 2017 -- Cs-131 Dose Distribution and Outcomes
IsoRay, Inc. 2019 -- Cs-131 Brachytherapy Product Information
Ochsner Clinic Foundation IRB Pro00013351 -- Study Protocol
