Surgery in High-Grade Insular Tumors: Oncological and Seizure Outcomes from 41 Consecutive Patients

Deepak Khatri; Kuntal Kanti Das; Jaskaran Singh Gosal; Gagandeep Attri; Amanjot Singh; Kamlesh Singh Bhaisora; Anant Mehrotra; Jayesh Sardhara; Pawan Kumar Verma; Arun Kumar Srivastava; Awadhesh Kumar Jaiswal; Sanjay Behari

doi:10.4103/ajns.AJNS_18_20

Surgery in High-Grade Insular Tumors: Oncological and Seizure Outcomes from 41 Consecutive Patients

Asian J Neurosurg. 2020 Aug 28;15(3):537-544. doi: 10.4103/ajns.AJNS_18_20. eCollection 2020 Jul-Sep.

Affiliations

¹ Department of Neurosurgery, Lenox Hill Hospital, New York, USA.
² Department of Neurosurgery, SGPGIMS, Lucknow, Uttar Pradesh, India.

Abstract

Background: Insular high-grade gliomas are uncommon and constitute approximately 10% of all intracranial high-grade gliomas. Several publications in the recent years have thrown substantial light in the understanding of insular low-grade gliomas. However, there is a paucity of information concerning the spectrum of high-grade lesions affecting the insula, the mode of presentation vis-à-vis low-grade gliomas, and the survival rates to modern therapy.

Aims and objectives: We aim to highlight various clinical patterns, histo-pathological spectrum and the survival rates in patients with high-grade insular lesions. Also, we explore the factors that govern favourable outcomes.

Materials and methods: A retrospective study of 41 patients operated for high-grade insular tumors at our institute between March 2010 to December 2018 was done to evaluate the clinico-radiological features, surgical nuances, survival rates and seizure outcomes.

Results: Raised intracranial pressure was the most frequent clinical presentation (n=28/41, 68.3%). Nearly 60% of the patients (n=25) had involvement of all four Berger-Sanai zones. The high-grade tumors encountered in our series were: glioblastoma (n=15), gliosarcoma (n=3), and embryonal tumor, not otherwise specified in 3 patients, while 21 patients had grade 3 astrocytoma. 33 out of 41 patients (80.5%) in our study showed excellent seizure control (ILAE grade 1A) at follow-up. Clinical presentation with seizures (P = 0.01, HR=0.3), WHO grade IV histopathology (P = 0.04, HR=3.7) and development of recurrence (P = 0.05, HR=5.5) were found to be independent predictors of OS.

Conclusion: Insular high-grade gliomas are commoner than thought and nearly half of these are grade IV tumors (51%). A presentation with seizures may indicate precursor low-grade gliomas and portend a better survival. A maximum "safe" surgical resection, keeping the postoperative quality of life in mind, should be the goal.

Keywords: Factors; glioblastoma; high-grade glioma; insular lobe; outcome; surgery; survival.