Effects of craniectomy defect on tumor-treating fields

Area of Science:

• Biomedical Engineering
• Oncology
• Medical Physics

Background:

• Tumor-treating fields (TTFields) are an FDA-approved treatment for glioblastoma, utilizing alternating electric fields.
• Effective TTFields delivery requires penetration through the skull to reach the gross tumor volume (GTV).
• The skull attenuates electric fields, suggesting craniectomy might improve TTFields penetration.

Purpose of the Study:

• To investigate the impact of craniectomy and subsequent defect filling on TTFields delivery to the GTV in glioblastoma.
• To analyze how biomaterials and the ratio of GTV to defect size influence electric field distribution.

Main Methods:

• Analysis of magnetic resonance imaging datasets from three glioblastoma patients, including one who underwent craniectomy.
• Generation of 3D finite element models to simulate electric field distribution, energy deposition, and current density.
• Virtual craniectomy analysis to assess the influence of defect geometry and biomaterial filling.

Main Results:

• Craniectomy defect geometry, with or without burr holes, did not significantly alter TTFields delivery to the GTV.
• Biomaterials used to fill the craniectomy defect, especially highly conductive ones like tantalum, significantly influenced electric field penetration.
• The relative size of the GTV to the defect size modulated TTFields coverage, with larger GTVs potentially enhancing coverage and eroded GTVs attenuating it.

Conclusions:

• Craniectomy, biomaterial choice for defect filling, and the GTV-to-defect size ratio can interact to modulate TTFields penetration.
• These findings have clinical relevance for optimizing personalized TTFields treatment strategies in glioblastoma patients.