Upfront frameless hypofractionated gamma knife radiosurgery for large posterior Fossa metastases.

in Neurosurgical review by Yavuz Samanci, Serhat Aydin, Ali Haluk Düzkalir, M Orbay Askeroglu, Selcuk Peker

TLDR

  • The study evaluated the use of upfront hf-GKRS for treating large brain tumors in the back of the brain, finding it to be a safe and effective option with controlled tumor growth in most patients.
  • Key findings include local control rates of 88.1% over a median follow-up of 6 months, with controlled primary tumor status associated with a lower risk of death.

Abstract

The management of large metastatic brain tumors (METs), particularly those in the posterior fossa (pf-METs), is challenging. While surgery can alleviate symptoms, it carries the risk of complications such as leptomeningeal disease (LMD). Upfront hypofractionated Gamma Knife radiosurgery (hf-GKRS) has shown promise as an alternative approach for managing large METs. This study assesses the efficacy and safety of upfront hf-GKRS for treatment-naïve large pf-METs. In this retrospective, single-center study, 40 patients with 42 pf-METs received hf-GKRS from October 2017 to June 2024. Patients eligible for the study were 18 years or older, had histologically confirmed malignancy, large pf-METs (> 4 cm), and a minimum of two follow-up MRI scans. The primary outcome was local control (LC), with secondary assessments of distant intracranial failure (DICF), intracranial progression-free survival (PFS), overall survival (OS), and toxicity. LC was achieved in 88.1% of pf-METs over a median follow-up of 6 months (mean: 13.7 months). LC rates at 6, 12, and 24 months were 95.8%, 95.8%, and 74.5%, respectively. Local failure (LF) occurred in 11.9% of cases, with a median recurrence time of 12 months. DICF was noted in 35% of patients, while no cases of LMD were reported. Intracranial PFS rates at 6, 12, and 24 months were 54.1%, 39.0%, and 16.7%, respectively, with a median PFS of 8 months. Symptomatic hydrocephalus developed in one patient (2.5%). Controlled primary tumor status (HR: 0.17, p = 0.036) was significantly associated with lower risk of death, while no other parameters were predictive of LC, DICF, or intracranial PFS. hf-GKRS demonstrates strong efficacy and safety as a primary treatment for selected, treatment-naïve large pf-METs over a relatively short follow-up duration. Further studies are warranted to refine patient selection, fractionation, and dosing strategies for this challenging population.

Overview

  • The study evaluates the efficacy and safety of upfront hypofractionated Gamma Knife radiosurgery (hf-GKRS) for treating large posterior fossa (pf) metastatic brain tumors.
  • The study included 40 patients with 42 large pf metastatic brain tumors, and the primary outcome was local control (LC).
  • The study aimed to explore the efficacy and safety of hf-GKRS as a primary treatment for selected, treatment-naïve large pf metastatic brain tumors.

Comparative Analysis & Findings

  • The study found that 88.1% of pf-METs had local control over a median follow-up of 6 months, with LC rates at 6, 12, and 24 months being 95.8%, 95.8%, and 74.5%, respectively.
  • Local failure occurred in 11.9% of cases, with a median recurrence time of 12 months, and distant intracranial failure was noted in 35% of patients.
  • Controlled primary tumor status was significantly associated with a lower risk of death, while other parameters were not predictive of local control, distant intracranial failure, or intracranial progression-free survival.

Implications and Future Directions

  • The study suggests that upfront hf-GKRS is a safe and effective treatment option for large pf-METs, and further studies are needed to refine patient selection, fractionation, and dosing strategies.
  • The study's findings highlight the importance of evaluating the relationship between primary tumor control and patient outcomes in future research.
  • Future studies may also explore the role of hf-GKRS in combination with other therapies, such as chemotherapy or immunotherapy, to improve treatment outcomes for large pf-METs.
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