Introduction: Glioblastoma (GBM) was the first cancer to be studied by the Cancer Genome Atlas Research Network (TCGA). The TCGA dataset defined four glioblastoma subtypes based on gene expression molecular classification (pro-neural, neural, classical, and mesenchymal), which have prognostic significance. The impact of EOR on survival has been well established. It is however not known if EOR is equally valuable between patients with “favorable” and “unfavorable” tumor genetics. Here we describe the impact of extent of surgical resection (EOR) on patient outcomes in relation to molecular tumor characteristics using a subset of the TCGA data. The goal of this study was to determine whether EOR influences outcomes based on TCGA subtype.
Methods: Preliminary analysis from 66 of the 120 patients with adult glioblastoma treated at HFH was analyzed for this study. Molecular classification and TCGA subtype was established according to existing protocol. Volumet-ric analysis of pre- and post-operative MRIs were performed to obtain EOR. ANOVA and Kaplan Meier survival analyses were performed to assess the relationship between EOR, TCGA molecular subtype in addition to over-all and progression free survival (OS/PFS).
Results: EOR was a significant independent predictor of OS and PFS (p=.005 and .009). Patients with gross total resec-tions (GTR) had a median OS and PFS of 18.28 and 8.91 months compared to 8.55 and 4.77 months for those with subtotal resections (STR) (Table 1). Tumors classified as proneuronal and neuronal were considered “favorable” and those classified as mesenchymal and classical were considered “unfavorable” based on previous published reports. Both favorable and unfavorable TCGA subtype tumors with GTR experienced longer OS (but not PFS) compared with STR (Figure 1).
Conclusions: GTR significantly improved OS and PFS regardless of tumor genetics. A better understanding of the role tumor genetics plays along side EOR may permit more informed surgical planning in the future.
Patient Care: This research will improve patient care by encouraging a better understanding of prognostic factors in patients with glioma that will lead to more effective treatment strategies.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the
importance of extent of tumor resection in glioma treatment, 2) Discuss common somatic mutations and classification schemes observed in glioblastoma 3) Describe known prognostic indicators in patients with glioblastoma that inform clinical decision making.