Feasibility evaluation of tumor treating fields for brainstem gliomas

Area of Science:

• Neurosurgery
• Medical Physics
• Oncology

Background:

• Tumor Treating Fields (TTFields) are FDA-approved for supratentorial glioblastoma.
• The feasibility of TTFields for infratentorial tumors, such as brainstem gliomas, is not well-established.
• Patient-specific modeling offers a potential solution for optimizing TTFields delivery in challenging tumor locations.

Purpose of the Study:

• To evaluate the efficacy of TTFields in brainstem gliomas using patient-specific modeling.
• To assess TTFields dose distribution with scalp-only transducer arrays in infratentorial tumors.
• To compare optimized TTFields arrays against standard layouts for brainstem glioma treatment.

Main Methods:

• Utilized MRI and CT imaging from seven brainstem glioma patients for TTFields planning.
• Defined clinical target volume (CTV) including a 3 mm peritumoral expansion around the gross tumor volume (GTV).
• Employed MAXPOINT® software for optimized scalp-only array layouts and finite element calculations to determine local minimum field intensity (LMiFI) and power density (LMiPD).

Main Results:

• MAXPOINT-optimized layouts significantly increased LMiFI compared to standard layouts across all regions (p ≤ 0.019).
• Median LMiFI in the GTV and CTV met or exceeded the therapeutic reference of 1.0 V/cm.
• Optimized arrays achieved higher LMiPD (p ≤ 0.006) and demonstrated the greatest improvement in the posterior fossa (median LMiFI 1.5 vs. 1.2 V/cm).

Conclusions:

• Patient-specific modeling with scalp-only arrays can achieve favorable TTFields intensities in brainstem gliomas.
• These findings support the prospective clinical evaluation of TTFields for infratentorial tumors.
• Optimized TTFields delivery shows promise for treating challenging brainstem gliomas.