A comparison of long-term survivors and short-term survivors with glioblastoma, subventricular zone involvement: a predictive factor for survival?

Objective: Long-term survival is rare in patients with glioblastoma (GBM). We set out to determine prognostic factors for patients with favorable and poor prognosis in regard of tumor localization to the subventricular zone (SZV). Methods: We reviewed the clinical records, pre-operative and post-operative MRI imaging of 50 LTS long-term survivors (LTS) (>3 years) and 50 short-term survivors (STS) (<1 year) with glioblastoma. These groups were matched for clinical characteristics being consistently associated with prolonged or shortened survival. All patients had undergone initial surgery or biopsy to confirm GBM diagnosis followed by radio- or chemoradiotherapy. Results: LTS had a median progression-free survival PFS of 25, 4 months (2, 3-97, 8 months) and overall-survival (OS) of 55, 9 months (38, 2-98, 6 months) compared to STS who had a significantly lower PFS of 4, 2 months (1, 4-10, 2 months) and OS of 6, 6 months (2, 2-11, 6 months) (each p<0,001). Survival analysis showed that age under 60 years (p<0,001), total resection status ( p<0,001) and tumor localization without SVZ contact (p=0,05) were significant factors for prolonged survival. Conclusion: Our findings underline that survival in GBM patients is heterogeneous and influenced by multiple factors. This study confirms that tumor location with regard to the SVZ is significantly associated with survival.