Neurocognitive Outcome and Seizure Freedom After Awake Surgery of Gliomas

Abstract

Objectives: Gliomas are often diagnosed due to epileptic seizures as well as neurocognitive deficits. First treatment choice for patients with gliomas in speech-related areas is awake surgery, which aims at maximizing tumor resection while preserving or improving patient's neurological status. The present study aimed at evaluating neurocognitive functioning and occurrence of epileptic seizures in patients suffering from gliomas located in language-related areas before and after awake surgery as well as during their follow up course of disease.

Materials and methods: In this prospective study we included patients who underwent awake surgery for glioma in the inferior frontal gyrus, superior temporal gyrus, or anterior temporal lobe. Preoperatively, as well as in the short-term (median 4.1 months, IQR 2.1-6.0) and long-term (median 18.3 months, IQR 12.3-36.6) postoperative course, neurocognitive functioning, neurologic status, the occurrence of epileptic seizures and number of antiepileptic drugs were recorded.

Results: Between 09/2012 and 09/2019, a total of 27 glioma patients, aged 36.1 ± 11.8 years, were included. Tumor resection was complete in 15, subtotal in 6 and partial in 6 patients, respectively. While preoperatively impairment in at least one neurocognitive domain was found in 37.0% of patients, postoperatively, in the short-term, 36.4% of patients presented a significant deterioration in word fluency (p=0.009) and 34.8% of patients in executive functions (p=0.049). Over the long-term, scores improved to preoperative baseline levels. The number of patients with mood disturbances significantly declined from 66.7% to 34.8% after surgery (p=0.03). Regarding seizures, these were present in 18 (66.7%) patients prior to surgery. Postoperatively, 22 (81.5%) patients were treated with antiepileptic drugs with all patients presenting seizure-freedom.

Conclusions: In patients suffering from gliomas in eloquent areas, the combination of awake surgery, regular neurocognitive assessment - considering individual patients´ functional outcome and rehabilitation needs - and the individual adjustment of antiepileptic therapy results in excellent patient outcome in the long-term course.

Keywords: awake surgery; epilepsy; glioma; neurocognition; neurocognitive outcome; quality of life.

Figure 1

Percent of impaired patients at T1 (preoperatively), T2 (after a median follow-up period of 4.1 months) and T3 (after a median follow-up period of 18.3 months). Long brackets mark results of the Cochran’s analysis (*=p < 0.05, **=p < 0.01), small brackets mark the post-hoc tests performed for serial follow up data (+=p < 0.05, dashed bracket p < 0.1). Complete data with Cochran Q’s and post-hoc tests for all domains is available as supplementary material ( Supplementary Table 1 ).

Figure 2

Individual changes (z-scores) t1 (preoperatively), t2 (after a median follow-up period of 4.1 months) and t3 (after a median follow-up period of 18.3 months). The domain “visuospatial functioning” was excluded because the underlying test has no variance of the standardized value in the performance range rated as unimpaired. *=p < 0.05, **=p < 0.01, dashed bracket p < 0.1.