Objective:

Characterize seizure burden and treatment among patients with Paraneoplastic Epilepsy. Quantify the number of patients with refractory seizures and evaluate candidacy for surgical resection.  

Background:

Seizures are a common feature of Paraneoplastic Syndrome. Existing literature suggests that some patients with Paraneoplastic Epilepsy have poor clinical outcomes even after treatment. These patients might meet criteria for drug-resistant epilepsy and surgical resection. 

Design/Methods:

Retrospective chart review of 45 (M=16, F=29) convenience-sampled patients diagnosed with Paraneoplastic Syndrome (PNS) between January 1, 2003 and October 31, 2023. Patients with seizures (n=26; M=12, F=14) were included in the analysis. Patients were divided into two groups based on PNS diagnosis: Anti-NMDA Receptor Encephalitis (n=10) and Other (Limbic Encephalitis (n=11), Autoimmune Encephalitis (n=3), Stiff Person Syndrome (n=2)). A two-tailed Mann-Whitney U test was utilized for statistical analysis (p<0.05). 

Results:

Significantly fewer ambulatory anti-epileptic drugs (AEDs) were trialed in the Anti-NMDAR group (median = 2.5) compared to the Other group (median = 4.0), U=10, Z=-3.68, p<0.01, effect size r=0.72. 77% of all patients with seizures were trialed on >2 AEDs. 70% of patients in the Anti-NMDAR group achieved seizure remission by one year after initial presentation, compared to 19% of the Other group. Median seizure duration was 3.0 months (IQR 2.0-5.0 months) in the Anti-NMDAR group and 33.0 months (IQR 8.8-47.3 months) in the Other group. 100% of patients in the Anti-NMDAR group and 50% of patients in the Other group achieved seizure remission by longitudinal follow-up (75.7 ± 50.9 months post initial presentation). Of patients with seizures at longitudinal follow-up (n=8), 88% had trialed >2 AEDs, 75% had evidence of localized seizures on EEG, and 75% had an abnormal MRI at presentation. 

Conclusions:

Mainstay treatments for Paraneoplastic Epilepsy are insufficient for an important subset of patients. Preliminary results provide justification for exploration of other epilepsy treatment options, to include resection.