Survival Determinants in Glioblastoma: An Insight into Biopsy-Only Patient Outcomes.

Abstract

Background: Glioblastoma is a challenge in neuro-oncology, with survival significantly influenced mainly by the extent of resection and molecular markers. Despite advancements, the prognosis for IDH-wildtype glioblastoma remains poor, particularly when surgical resection is not possible. However, some patients exhibit unexpectedly extended survival despite the extent of resection. This study aims to analyze the determinants that contribute to these atypical survival rates among glioblastoma patients who have had solely biopsy procedures. Methods: We conducted a retrospective analysis of patients diagnosed with IDH-wildtype glioblastomas at our institution from 2017 to 2021, who underwent biopsy only. This study focused on evaluating the impact of demographic characteristics, clinical features, molecular markers, and treatment modalities on survival outcomes (overall survival (OS) and progression-free survival (PFS)). Statistical analyses included survival analysis and logistic regression for evaluating associations between OS and pre-operative characteristics and post-operative treatments. Results: The cohort included 99 patients, with a median age at diagnosis of 65.5 years. Median OS and PFS were 6.0 and 3.6 months, respectively. The multivariate analysis revealed that higher Karnofsky Performance Status (KPS) scores before biopsy, no contrast uptake on imaging, and any adjuvant therapy, particularly the use of bevacizumab, were independently associated to increased OS (HR = 0.97, p = 0.009. HR = 0.7, p = 0.015; HR = 0.27, p = 0.002, respectively). Out of 99 patients, 77.8% survived past the 3-month threshold, with 87.0% of this receiving adjuvant treatment. Only 8% of patients survived past 24 months, and in this group of patients, MGMT methylation was observed in just 25% of cases. Kaplan-Meier analysis indicated a better prognosis with any type of adjuvant therapy across all patients, particularly so in those with KPS ≥ 70. Age did not significantly affect survival outcomes (OR = 1.00, p = 0.835). Conclusion: Our findings reveal that any adjuvant treatment (whether chemotherapy and radiotherapy combined, chemotherapy alone, or bevacizumab), no contrast uptake on imaging, and higher pre-operative KPS are key determinants of survival in IDH-wildtype glioblastoma and should therefore be considered when deciding whether to perform a biopsy.