Zap-X Radiosurgery System: Initial Clinical Experience in a Recurrent Gamma Knife Case Series

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Physics

Background:

• The ZAP-X Gyroscopic Radiosurgery System offers advanced gyro-stereotactic irradiation for intracranial lesions.
• This study evaluates ZAP-X for intracranial lesions that recurred following prior Gamma Knife (GK) treatment.

Purpose of the Study:

• To report the initial treatment outcomes of ZAP-X in patients with recurrent intracranial tumors after GK therapy.
• To assess the progression control rate, lesion reduction, and adverse events associated with ZAP-X treatment.

Main Methods:

• Six patients with recurrent intracranial tumors post-GK were treated with ZAP-X between April and August 2023.
• Primary endpoint: 6-month progression control rate. Secondary endpoints: lesion reduction, tumor doubling time (TDT), and adverse events.

Main Results:

• 100% progression control rate at six months across six evaluated lesions (meningiomas, solitary fibrous tumor, auditory neuroma, glomus tumor, metastatic tumor).
• Two partial responses and four stable diseases observed; mean follow-up was 10.6 months.
• Adverse events were minimal (16.6%), with a noted correlation between pre-intervention TDT and post-intervention reduction rate.

Conclusions:

• ZAP-X demonstrates significant anti-tumor efficacy and adequate tolerability in patients with recurrent intracranial tumors post-GK.
• ZAP-X represents a promising new treatment option for patients with relapsed or refractory disease.
• Further research with larger cohorts and longer follow-up is warranted to fully elucidate ZAP-X treatment outcomes and safety.