Extent of resection in glioblastoma: a 10-year local survival analysis

Abstract

Abstract Aims The impact on extent of resection (EOR) in glioblastoma has been well documented. It is clear that gross-total resection (GTR) confers best overall survival (OS), however the minimum EOR required to confer a survival benefit over biopsy is debated. Recent studies favour partial resection (PR) over biopsy for IDH-wildtype, MGMT-unmethylated tumours. We describe our experiences locally with these principles in mind. Method Retrospective evaluation of a single surgeon cohort. All patients over 18 years old, undergoing a surgical treatment for histologically confirmed GBM in the stated period were included. We collected information on demographics, tumour volume, EOR, complications, adjuvant therapies, molecular profile, and OS. We used log rank tests and Cox Proportional Hazards Models to identify factors associated with OS. Results The patient and tumour characteristics of our cohort were similar to those documented in the literature. The mean age was 56.6 years. 72 patients underwent biopsy and 202 had debulking surgery. Median OS was 11 months. Of those debulked, gross-total resection was achieved in 41 patients (20%); associated median OS was 29 months. Patients receiving partial resection (defined as EOR <80%) had no clear survival benefit over patients undergoing biopsy (median OS 6 vs 5 months) but had a higher rate of post-op neurological deficit (3% vs 12%). Tumour molecular profile appeared to influence survival outcome in a manner comparable to worldwide experience. Conclusion In our experience, partial resection is not a justifiable surgical aim in the typical glioblastoma cohort. The limited benefit that it may confer over biopsy appears to be outweighed by the risk of neurological deficit that affects quality and probably quantity of life. This finding applies to our glioblastoma population in general as well as those specifically with an MGM-unmethylated tumour.