Introduction: Low and high-grade gliomas can arise within the insula. This study compares biopsy versus resection for the treatment of insular gliomas, and quantifies extent of resection (EOR), defines morbidity, and identifies prognostic factors on survival.
Methods: All adult patients with a diagnosis of an insular glioma at our institution between 1996 and 2012 were included. Clinical and outcome data were collected. Gliomas were classified by location using a modified classification system.
Results: The study included 25 biopsy and 161 resection patients, with no significant differences in baseline clinical and tumor characteristics between the groups. Overall survival was significantly longer (P=0.05 in all instances) with resection compared to biopsy for grade II (medians 10.9 and 5.2 years, respectively), III (medians 10.1 and 2.6 years, respectively) and IV gliomas (medians 1.8 and 1.1 years, respectively). Progression-free survival was significantly longer with resection versus biopsy for grade III (medians 5.9 and 1.1 years, respectively) and IV gliomas (medians 1.1 and 0.6 years, respectively), and non-significantly improved for grade II gliomas (medians 6.1 years in the resection group and not reached in the biopsy group). Malignant progression-free survival was significantly longer with resection versus biopsy for grade III gliomas (medians 6.1 and 1.3 years, respectively) and non-significantly improved for grade II gliomas (medians 8.1 in the resection group and not reached in the biopsy group). Factors associated with longer survival included younger age, higher Karnofsky Performance Status score, histology of oligodendroglioma or mixed oligoastrocytoma, and greater EOR. Significantly lower EOR and higher neurologic deficits occurred for gliomas with posterior insular involvement and/or medial extension.
Conclusions: Resection of both low and high-grade insular gliomas improves survival compared to biopsy. For insular gliomas with a posterior component and/or medial extension, resection comes with a significantly lower EOR and higher rates of post-operative neurologic deficits.
Patient Care: Establishes the role of resection for the treatment of insular gliomas. Clinically and surgically useful classification system introduced. Prognostic factors discussed.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of safe, maximum resection of insular gliomas and its affect on survival.
References: see Manuscript