Neurological outcome and memory performance in patients with 10 or more brain metastases treated with frameless linear accelerator (LINAC)-based stereotactic radiosurgery

Purpose: To assess the neurocognitive function and neurological toxicity of frameless linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) in patients with 10 or more brain metastases (BM).

Patients and methods: Forty consecutive adult patients who received SRS for ten or more 10 BM < 3 cm in maximum size were evaluated. All plans were generated using a single-isocenter multiple-target (SIMT) SRS technique with doses of 22 Gy for lesions < 2 cm and 16-18 Gy for those ≥ 2 cm in size. Survival analyses were estimated by Kaplan-Meier method from the date of SRS. Neurocognitive function using the Hopkins verbal learning test-revised (HVLT-R) and activity of daily living scale (ADLS) were collected prospectively at baseline and at 3,6 and 12-month follow-up. Toxicity was assessed by the National Cancer Institute Common Toxicity Criteria for Adverse Events (Version 5.0).

Results: With a median follow-up of 10.8 months, 1-year survival and local control rates were 65% and 86%, respectively. Grade 2 or 3 toxicity occurred in eleven patients, being associated with radiological changes suggestive of radiation necrosis in seven patients. Three months after SRS, the mean relative decline was 14.2% for HVLT-R delayed recall, 12.3% for HVLT-R recognition, and 9.8% for HVLT-R total recall. A significant deterioration of HVLT-R scores ranged from 5.5 to 18.7% of patients at different time points. ADLS scores declined over time, but changes were not significant.

Conclusions: SRS is an effective and safe approach for patients with 10 or more BM able to maintain the pretreatment neurocognitive function in the majority of patients.