Age is not associated with risk for patients with low grade glioma in the era of molecular diagnostics
William Curry, Pamela Jones, Bryan Choi
Introduction: Since publication of the long-term results of the Radiation Therapy Oncology Group 9802 clinical trial, patients with low grade glioma (LGG) have been divided into high and low-risk categories based on age (> or <40) and extent of resection.
Objective: We re-examine the independent impact of age in the context of the WHO 2016 diagnostic criteria, which incorporate tumor genetics.
Methods: The authors queried institutional databases for 2 large academic medical centers for patients with new tissue diagnosis of LGG between 2008 and 2013. Clinicopathological characteristics including relevant molecular data and therapeutic interventions were recorded. Cox multivariate analysis was performed to identify variables that significantly predicted overall survival.
Results: We identified 326 patients with LGG. The median age was 43.1 years. Gross total resection was achieved in 79 patients (24%). In a multivariate analysis considering age, extent-of-resection, and the use of adjuvant radiation or chemotherapy, we confirmed that stratification by age (i.e., younger or older than 40) was predictive of overall survival (OS) (HR 1.03 [95% CI 1.01—1.05], P < 0.001). However, when controlling for IDH mutation status, there was no correlation between age and OS, despite persistent association of the remaining studied variable, including subtotal resection (HR 0.37 [95% CI 0.16—0.88], P = 0.02)) and the use of adjuvant radiation (HR 2.28 [95% CI 1.16—4.46], P = 0.02) or chemotherapy (HR 2.15 [95% CI 1.12—4.14], P = 0.02)
Conclusions: Age is not dependently associated with risk in low grade gliomas when accounting for molecular status. This has important implications for treatment decisions in older patients that undergo gross total resection of these tumors.