Intraoperative radiotherapy after neurosurgical resection of brain metastases as institutional standard treatment– update of the oncological outcome form a single center cohort after 117 procedures - Scorecard - MDSpire
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Intraoperative radiotherapy after neurosurgical resection of brain metastases as institutional standard treatment– update of the oncological outcome form a single center cohort after 117 procedures
Clinical Scorecard: Update on Oncological Outcomes Following Intraoperative Radiotherapy After Neurosurgical Resection of Brain Metastases: A Single-Center Cohort Analysis of 117 Cases
Intraoperative radiotherapy (IORT) with 50 kV x-rays delivers focal irradiation to the resection cavity with steep dose gradients, higher relative biological efficacy, and immediate treatment post-surgery, potentially reducing local recurrence and radio necrosis
Target Population
Patients undergoing neurosurgical resection of brain metastases with a minimum 5 mm distance from critical structures (optic tract/brainstem)
Care Setting
Single-center neurosurgical and radiation oncology department with multidisciplinary tumor board guidance
Key Highlights
IORT provides a focal radiation dose immediately after tumor resection, shortening the interval between surgery and radiotherapy to zero
Local control rate of the resection cavity after IORT was 90.5%, with an estimated 1-year local control of 84.2%
Median overall survival was 18.2 months with 1-year survival of 57.7%; distant brain control at 1 year was 47.9%, and leptomeningeal disease occurred in 10.4% at 1 year
Guideline-Based Recommendations
Diagnosis
Confirm malignancy of resected brain metastases by frozen section intraoperatively
Use MRI to assess lesion size and distance from critical structures prior to surgery
Management
Perform microsurgical resection of brain metastases followed by immediate IORT with 50 kV x-rays using spherical applicators sized to the resection cavity
Prescribe radiation dose to the applicator surface, ensuring direct contact with cavity walls
Exclude patients with metastases closer than 5 mm to optic tract/brainstem or centrally located/posterior fossa lesions as per neurosurgeon discretion
Treat additional non-resected brain lesions with stereotactic radiotherapy (SRT) or whole brain irradiation (WBI) as clinically indicated
Monitoring & Follow-up
Conduct standardized follow-up with brain MRI every 3 months post-treatment
Monitor for local recurrence, distant brain metastases, and leptomeningeal disease
Risks
Potential for leptomeningeal disease development (10.4% at 1 year)
Risk of radio necrosis is potentially lower due to steep dose gradients but requires monitoring
Limited data on toxicity; patient selection criteria aim to minimize risk to critical brain structures
Patient & Prescribing Data
105 patients with 117 resected brain metastases, median age 65 years, mostly RPA class 2, with predominant histologies including non-small-cell lung cancer, malignant melanoma, and breast carcinoma
Median applied IORT dose was 20 Gy; treatment was well tolerated with high local control and survival outcomes; IORT became predominant cavity treatment due to patient preference
Clinical Best Practices
Ensure multidisciplinary tumor board evaluation for patient selection and treatment planning
Select spherical applicator size to match resection cavity for optimal dose delivery
Maintain a minimum 5 mm safety margin from critical structures to reduce toxicity
Implement immediate IORT post-resection to minimize interval between surgery and radiotherapy
Follow standardized imaging surveillance protocol with 3-monthly MRI to detect recurrence early
by Klaus-Henning Kahl, Philipp E. Krauss, Maria Neu, Christoph J. Maurer, Sabine Schill-Reiner, Zoha Roushan, Eva Laukmanis, Christian Dobner, Tilman Janzen, Nikolaos Balagiannis, Björn Sommer, Georg Stüben, Ehab Shiban
