Survival and prediction of distant recurrence in glioblastoma

INTRODUCTION: Glioblastoma is the most prevalent and aggressive primary tumor of the nervous system. The condition manifests with a high rate of recurrence, predominantly in a localized pattern. The impact of distant recurrence on survival and the associated factors are a controversial subject. This study aims to determine whether the pattern of distant recurrence exerts any influence on progression-free survival, survival after first progression, and overall survival in patients with de novo glioblastoma and low residual tumor volume (RTV) < 5 cc. It also aims to identify which factors predict distant recurrence. MATERIAL AND METHODS: A retrospective single-center cohort study included patients aged 18 years or over with de novo glioblastoma and RTV < 5 cc after histological diagnosis, who were treated between 2017 and 2023 in our center. Kaplan-Meier curves were utilized for time-to-event analyses. Risk factors were assessed by univariable analysis and logistic regression. RESULTS: The analysis encompassed 102 patients with a median survival period of 12.9 months. Distant recurrence was associated with a more extended progression-free survival (11.9 months; p = 0.003) and overall survival (21.5 months; p = 0.021) compared with the remaining patterns (6.1 and 12.7 months, respectively), with no significant impact on survival after the first progression. Epidermal growth factor receptor (EGFR) amplification (odds ratio [OR] = 3.42, 95% confidence interval [CI]: 1.14-10.60; p = 0.029) and Ki-67 < 30% (OR = 6.15, 95% CI: 1.12-33.67; p = 0.036) were identified as independent risk factors for distant recurrence. CONCLUSIONS: Distant recurrence in glioblastomas with low tumor burden after diagnosis is associated with superior progression-free survival and overall survival compared with other recurrence patterns. The EGFR amplification and Ki-67 < 30% were identified as independent risk factors for distant progression. CLINICAL IMPLICATIONS: The study underscores the significance of incorporating molecular profiling into decision-making processes for patients with glioblastoma. Furthermore, stratification by recurrence patterns has the potential to enhance the efficacy of future clinical trials.