Cognitive Functions in Repeated Glioma Surgery

Abstract

Low-grade gliomas (LGG) are slow-growing brain tumors infiltrating the central nervous system which tend to recur, often with malignant degeneration after primary treatment. Re-operations are not always recommended due to an assumed higher risk of neurological and cognitive deficits. However, this assumption is relatively ungrounded due to a lack of extensive neuropsychological testing. We retrospectively examined a series of 40 patients with recurrent glioma in eloquent areas of the left hemisphere, who all completed comprehensive pre- (T3) and post-surgical (T4) neuropsychological assessments after a second surgery (4-month follow up). The lesions were most frequent in the left insular cortex and the inferior frontal gyrus. Among this series, in 17 patients the cognitive outcomes were compared before the first surgery (T1), 4 months after the first surgery (T2), and at T3 and T4. There was no significant difference either in the number of patients scoring within the normal range between T3 and T4, or in their level of performance. Further addressing the T1–T4 evolution, there was no significant difference in the number of patients scoring within the normal range. As to their level of performance, the only significant change was in phonological fluency. This longitudinal follow-up study showed that repeated glioma surgery is possible without major damage to cognitive functions in the short-term period (4 months) after surgery.

Repeated Awake Surgical Resection(s) for Recurrent Diffuse Low-Grade Gliomas: Why, When, and How to Reoperate?

“…Indeed, when comparing results of the awake mapping performed during reoperation with those obtained during the first surgery, changes in the functional organization were detected (30,32). Such a remapping has been made possible due to the slow kinetics of recurrent DLGG, as illustrated by the long delay between the initial and second surgery, i.e., with a mean interval between 3 to 6.75 years (24,25,29,30,32,(35)(36)(37)(38). This neuroplastic potential explains why the EOR does not significantly differ between the first surgery and reoperation (27,29,34,36,37), or can even been greater with no additional neurological or neurocognitive deficit (38).…”

“…Interestingly, OS is correlated to the extent of resection (EOR), because the presence of residual glioma at either the initial (p = 0.007) or second (p = 0.001) surgery was associated with significantly shorter OS (28). The EOR did not differ between initial surgery and reoperation, with a mean EOR from 72% to 94% and a mean tumor residual volume from 3.1 to 8.8 ml (27,29,34,(36)(37)(38). Therefore, the benefit of repeat operations on survival is likely related to the cytoreduction effect, capable to delay DLGG transformation, as already demonstrated after the first surgery (2).…”

“…Moreover, two recent series investigated cognitive outcomes by performing an extensive neuropsychological before and after repeat awake surgery in patients with DLGG (36,38). Capo et al (36) found a global preservation of the level of performance in 40 patients, despite changes in phonological fluency.…”

“…Moreover, two recent series investigated cognitive outcomes by performing an extensive neuropsychological before and after repeat awake surgery in patients with DLGG (36,38). Capo et al (36) found a global preservation of the level of performance in 40 patients, despite changes in phonological fluency. Ng et al (38) examined 62 patients, of which eight (12.9%) experienced a cognitive deficit before reoperation: 3 months following reoperation, four additional patients (6.5%) had a cognitive worsening, whereas eight (12.9%) patients improved in comparison with the preoperative status-the others were stable.…”

Brain Mapping: Real-Time Neuropsychological Testing Experience during Low-Grade Tumor Resection

“…We retrospectively examined a series of 40 patients undergoing recurrent surgery in the left hemisphere, mainly in the left insular cortex and in the left inferior frontal gyrus (14). The study first compared the pre-and post-surgical neuropsychological status after first and second surgery.…”