Butterfly glioblastoma: Clinical characteristics, treatment strategies and outcomes in a population-based cohort

Abstract

Background: Butterfly glioblastoma is a rare subgroup of glioblastoma with a bihemispheric tumor crossing the corpus callosum, and is associated with a dismal prognosis. Prognostic factors are previously sparsely described and optimal treatment remains uncertain. We aimed to analyze clinical characteristics, treatment strategies, and outcomes from butterfly glioblastoma in a real-world setting.

Methods: This retrospective population-based cohort study included patients diagnosed with butterfly glioblastoma in Western Norway between 01/01/2007 and 31/12/2014. We enrolled patients with histologically confirmed glioblastoma and patients with a diagnosis based on a typical MRI pattern. Clinical data were extracted from electronic medical records. Molecular and MRI volumetric analyses were retrospectively performed. Survival analyses were performed using the Kaplan-Meier method and Cox proportional hazards regression models.

Results: Among 381 patients diagnosed with glioblastoma, 33 patients (8.7%) met the butterfly glioblastoma criteria. Median overall survival was 5.5 months (95% CI 3.1-7.9) and 3-year survival was 9.1%. Hypofractionated radiation therapy with or without temozolomide was the most frequently used treatment strategy, given to 16 of the 27 (59.3%) patients receiving radiation therapy. Best supportive care was associated with poorer survival compared with multimodal treatment [adjusted hazard ratio 5.11 (95% CI 1.09-23.89)].

Conclusion: Outcome from butterfly glioblastoma was dismal, with a median overall survival of less than 6 months. However, long-term survival was comparable to that observed in non-butterfly glioblastoma, and multimodal treatment was associated with longer survival. This suggests that patients with butterfly glioblastoma may benefit from a more aggressive treatment approach despite the overall poor prognosis.

Keywords: 3D volumetric; bihemispheric glioma; butterfly glioblastoma; clinical outcomes; survival.

Figure 1.

Median [interquartile range (IQR)] contrast-enhancing tumor volume in T1-weighted magnetic resonance imaging (MRI) and median (IQR) volume of tumor-associated non-enhancing hyperintense lesions in T2-weighted and/or fluid-attenuated inversion recovery (FLAIR) MRI according to tumor location in 33 patients diagnosed with butterfly glioblastoma between 01/01/2007 and 31/12/2014.

Figure 2.

The Kaplan–Meier curves of survival probability in 33 patients diagnosed with butterfly glioblastoma between 01/01/2007 and 31/12/2014. Cumulative survival in months. Survival by (a) age, (b) surgical resection, (c) number of treatment modalities, and (d) chemoradiotherapy regimen. Comparison of groups by log rank test. P-values < .05 were considered statistical significant.