Patients with brain metastases have a significantly increased risk of seizures, with a higher incidence in patients with melanoma, African American patients, patients with significant intracranial disease burden, and patients with metastases to epileptogenic intracranial sites, according to the study results published in Neurology.
Previous studies have provided varying estimates of the proportion of patients diagnosed with brain metastases who experienced seizures. The aim of the current study was to assess the incidence and risk factors for developing seizures in non-seizure patients with brain metastases.
In this retrospective study, researchers used data from Surveillance, Epidemiology, and End-Results-Medicare to identify 15,863 patients who were 66 or older between the ages of 66 and 2016 and who were diagnosed with brain metastases. In addition, an institutional analysis was performed and 1,453 seizure-naive patients with newly diagnosed brain metastases who were treated at Brigham and Women’s Hospital / Dana-Farber Cancer Institute between 2000 and 2015 were included.
Among 15,863 Medicare patients without seizures at diagnosis of brain metastasis, 1588 (10%) then developed seizures, with rates of seizure development in patients with melanoma being one year higher than in patients without (13.0% versus 8.3%; P <0.001 )) and increased rates in African American patients than in non-African American patients (10.9% versus 8.4%; P = 0.005).
In the adapted regression models, African-American patients were compared to white patients (hazard ratio)[HR]1.45; 95% CI, 1.22-1.73; P <0.001), higher household income at postcode level (HR 1.04; 95% CI 1.02-1.07; P = 0.001), urban vs. non-urban / unknown residence (HR 1.41; 95% CI 1, 17-) 1.70; P <0.001), melanoma for non-small cell lung cancer (HR 1.44; 95% CI 1.20-1.73; P <0.001) and receiving brain-directed stereotactic radiation against non-stereotactic brain-directed radiation (HR 1.67; 95% CI 1.44-1.94; P <0.001) were associated with an increased risk of developing seizures.
Of 1,453 non-seizure patients diagnosed with brain metastases, 169 (11.6%) subsequently developed seizures. Similarly, the risk of seizures was higher in patients with melanoma than in those without melanoma (15.0% versus 5.9%; P <0.001). The risk was higher in patients with more than 4 brain metastases than in patients with no more than 4 brain metastases (8.4% versus 6.9%; P = 0.05) and in patients with metastases in high-risk than low-risk locations ( 9.8% versus 2.0%, P <0.001).
In the adapted regression models, melanomas and non-small cell lung cancer (HR, 1.70, 95% CI, 1.09-2.64; P = 0.02) were larger than 4 brain metastases with intracranial presentation (HR, 1.60, 95% CI, 1.12-2.29; P = 0.01), presence of brain metastases in a high risk location with intracranial presentation (HR, 3.62, 95% CI, 1.60-8.18; P = 0.002) and lack of local brain-guided therapy (HR, 3.08, 95% CI, 1.45-6.52, P = 0.003) were associated with a higher risk of developing seizures.
The study had several limitations, including those secondary to the use of information to identify cancer metastases, incomplete data availability, and a lack of data on the risk of developing seizures throughout the patient’s disease course.
“Given that seizures can cause serious harm and significantly affect the quality of life of patients with BrM [brain metastases]These results may be helpful in advising patients about individual seizure risk and may influence future studies to evaluate the role of prelimitation of ASM [anti-seizure medications] for particularly vulnerable subgroups, ”concluded the study researchers.
Disclosure: One of the authors of the study stated that he was part of the pharmaceutical industry. For a full list of the authors’ information, see the original reference
Lamba N., Catalano PJ, Cagney DN, et al. Seizures in patients with brain metastases: a population and institutional level analysis. Neurology. Published online January 5, 2021. doi: 10.1212 / WNL.0000000000011459