Lok Edwin, Chang Bryant, Vega Rafael, Haack Monika, Wong Eric T
Division of Hematology/Oncology, Department of Medicine, Brown University Health & Rhode Island Hospital, Providence, Rhode Island, USA.
Brain Tumor Center & Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Neurooncol Adv. 2025 Feb 25;7(1):vdaf045. doi: 10.1093/noajnl/vdaf045. eCollection 2025 Jan-Dec.
Tumor-treating fields (TTFields) are alternating electric fields approved for the treatment of glioblastoma. They must penetrate through the skull to reach the gross tumor volume (GTV) in the brain. Since the skull is an attenuator of electric fields, removal of a section of cortical bone by craniectomy may facilitate the delivery of TTFields into the GTV.
We identified a glioblastoma patient who underwent craniectomy for evacuation of a subdural empyema. The patient subsequently received standard adjuvant treatment with TTFields plus temozolomide without replacement of the skull defect. Post-acquisition magnetic resonance imaging datasets were obtained from this index patient and 2 others for virtual craniectomy analysis. After anatomic delineation, a 3-dimensional finite element mesh was generated and then solved for the distribution of applied electric fields, rate of energy deposition, and current density at the GTV.
The geometry of craniectomy defect alone, with or without burr holes, did not alter TTFields delivery to GTV. Biomaterials filling the defect could significantly influence electric field penetration, particularly when they are highly conductive at 10 S/m or 7.76 × 10 S/m as in tantalum. The ratio of GTV relative to defect size also enhanced or attenuated TTFields coverage when the GTV was expanded or eroded, respectively.
Craniectomy, biomaterials filling the defect, and the ratio of GTV relative to defect size may interact in a combinatorial fashion in modulating TTFields penetration into the brain. These findings are clinically relevant for personalized TTFields treatment.
肿瘤治疗电场（TTFields）是已被批准用于治疗胶质母细胞瘤的交变电场。它们必须穿透颅骨才能到达大脑中的大体肿瘤体积（GTV）。由于颅骨是电场的衰减器，通过颅骨切除术去除一部分皮质骨可能有助于将TTFields输送到GTV。
我们确定了一名因硬膜下积脓引流而接受颅骨切除术的胶质母细胞瘤患者。该患者随后接受了TTFields联合替莫唑胺的标准辅助治疗，未进行颅骨缺损修复。从该索引患者和另外2名患者获取了术后磁共振成像数据集，用于虚拟颅骨切除术分析。在进行解剖描绘后，生成三维有限元网格，然后求解GTV处的外加电场分布、能量沉积速率和电流密度。
单独的颅骨切除缺损的几何形状，无论有无钻孔，均未改变TTFields向GTV的输送。填充缺损的生物材料可显著影响电场穿透，特别是当它们具有10 S/m或7.76×10 S/m的高导电性时，如钽。当GTV扩大或缩小，GTV相对于缺损大小的比例也会增强或减弱TTFields的覆盖范围。
颅骨切除术、填充缺损的生物材料以及GTV相对于缺损大小的比例可能以组合方式相互作用，调节TTFields穿透进入大脑的情况。这些发现对于个性化TTFields治疗具有临床相关性。
