Surgical, functional, and oncological considerations regarding awake resection for giant diffuse lower-grade glioma of more than 100 cm3

Abstract

OBJECTIVE Surgery for giant diffuse lower-grade gliomas (LGGs) is challenging, and very few data have been reported on this topic in the literature. In this article, the authors investigated surgical, functional, and oncological aspects in patients who underwent awake resection for large LGGs with a volume > 100 cm3. METHODS The authors retrospectively reviewed a consecutive cohort of patients who underwent surgery in an awake condition for an LGG (WHO grade 2 with possible foci of grade 3 transformation) with a volume > 100 cm3. RESULTS A total of 108 patients were included, with a mean age of 36.1 ± 8.5 years. The mean presurgical LGG volume was 136.7 ± 34.5 cm3. In all but 2 patients a disconnection resective surgery up to functional boundaries was possible thanks to active patient collaboration during the awake period. At 3 months of follow-up, all but 1 patient had a normal neurological examination, with a mean Karnofsky Performance Status (KPS) score of 89.8 ± 10.36. In all patients with preoperative epilepsy, there was postoperative control or significant reduction of seizure events. Moreover, 85.1% of patients returned to work. The mean extent of resection (EOR) was 88.9% ± 7.0%, with a mean residual tumor volume (RTV) of 16.3 ± 12.0 cm3 (median RTV 15 cm3). Pathological examination revealed 73 grade 2 gliomas (67.6%; 26 oligodendrogliomas and 47 astrocytomas) and 35 gliomas with foci of grade 3 (32.4%; 19 oligodendrogliomas and 16 astrocytomas). During the postoperative period, 93.6% of patients underwent adjuvant chemotherapy with a median interval between surgery and first chemotherapy of 14 months (IQR 2–26 months), and 55% of patients had radiotherapy with a median interval of 38.5 months (IQR 18–59.8 months). At the last follow-up, 69.7% of patients were still alive with a median follow-up of 62 months (IQR 36–99 months). Overall survival (OS) rates at 1, 5, and 10 years were 100% (95% CI 0.99–1), 80% (95% CI 0.72–0.9), and 58% (95% CI 0.45–0.73), respectively. The median OS was 138 months. In multivariable Cox regression analysis, RTV was established as the only independent prognostic factor for survival. CONCLUSIONS With the application of rigorous surgical methodology based on functional-guided resection, resection of giant LGGs (volume > 100 cm3) can be reproducibly achieved during surgery with patients under awake mapping with both favorable functional results (< 1% permanent neurological worsening) and favorable long-term oncological outcomes (median OS > 11 years, with a more significant benefit when the RTV is < 15 cm3).