Stereotactic radiosurgery for resected brain metastasis: Cavity dynamics and factors affecting its evolution

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Imaging

Background:

• Brain metastases treatment often involves surgery followed by stereotactic radiosurgery (SRS).
• Understanding post-surgical cavity volume changes is crucial for optimizing SRS planning.
• Predictors of cavity volume dynamics require further investigation.

Purpose of the Study:

• To analyze changes in post-surgical cavity volume for brain metastases.
• To identify predictors of cavity volume changes, including time from surgery and tumor characteristics.
• To inform treatment planning for post-operative SRS.

Main Methods:

• Retrospective analysis of 59 patients with resected brain metastases treated with SRS.
• 3D segmentation of pre-operative tumor and post-operative cavity volumes using MRI.
• Calculation of volume changes and analysis of predictors like tumor size, dural involvement, and time interval.

Main Results:

• Overall significant volume reduction observed between tumor and cavity volumes.
• Larger tumors showed significant volume reduction (11.6%), while smaller tumors increased in volume (34.4%).
• Tumor size (>3cm), dural involvement, and time from surgery were significant predictors of volume change.

Conclusions:

• Tumor size, dural involvement, and longer time post-surgery predict cavity volume reduction.
• Early post-surgical intervals (<21 days) may involve larger cavities, potentially leading to increased irradiation of normal tissue, especially for smaller tumors.