Outcomes of Gamma Knife Radiosurgery for Brain Metastases in the Motor Cortex

Neurosurgery. 2024 Mar 1;94(3):606-613. doi: 10.1227/neu.0000000000002716. Epub 2023 Oct 12.

Abstract

Background and objectives: To study the clinical, imaging, and survival outcomes in patients with motor cortex brain metastases treated with stereotactic radiosurgery (SRS).

Methods: Imaging and clinical data were obtained from our prospective patient registry. Tumor volumes were obtained from serial imaging data.

Results: The outcomes of 208 patients with metastases involving the motor cortex who underwent SRS between 2012 and 2021 were analyzed. A total of 279 metastases (0.01 cm 3 -12.18 cm 3 , mean 0.74 cm 3 ) were irradiated. The SRS margin dose varied from 10 to 20 Gy (mean 16.9 Gy). The overall tumor control rate was 97.8%. Perilesional edema was noted in 69 (25%) tumors at presentation. Adverse radiation effects (ARE) were noted in 6% of all tumors but were symptomatic in only 1.4%. Median time to appearance of symptomatic ARE was 8 months. Edema without ARE was observed in 13%. New focal seizures were noted in 5 patients (2%) and new generalized seizures in 1 patient (0.3%). Thirty-six patients (17%) presented with motor deficits. At final follow-up, 32 (85%) were improved or unchanged, 13 (41%) had a normal examination, 10 (31%) had mild deficits, and 9 (28%) still had moderate deficits. New remote brain metastases were found in 31% of patients at a median of 8 months. After treatment, the Karnofsky performance score distribution of the population showed an overall right shift and a median survival of 10 months. Patients with incidentally found brain metastases had significantly better survival than those presenting with deficits (median 13 vs 9 months) ( P = .048). Absence of a neurological deficit, recursive partitioning analysis Class I and II, and dose >18 Gy were each associated with a significant survival advantage.

Conclusion: SRS for motor cortex metastases is safe in most patients and effective in providing tumor control. Patients treated before neurological deficits develop show better outcomes.

MeSH terms

  • Brain Neoplasms* / pathology
  • Brain Neoplasms* / radiotherapy
  • Brain Neoplasms* / surgery
  • Humans
  • Motor Cortex* / pathology
  • Prospective Studies
  • Radiation Injuries* / etiology
  • Radiosurgery* / methods
  • Retrospective Studies
  • Seizures / etiology
  • Treatment Outcome