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ePoster Display

355P - Butterfly glioblastoma: Treatment strategies and clinical outcome


16 Sep 2021


ePoster Display


Clinical Research;  Survivorship;  Supportive and Palliative Care

Tumour Site

Central Nervous System Malignancies


Line Bjorland


Annals of Oncology (2021) 32 (suppl_5): S516-S529. 10.1016/annonc/annonc674


L.S. Bjorland1, E. Farbu2, B. Gilje1, Ø. Fluge3, R. Mahesparan4

Author affiliations

  • 1 Department Of Hematology And Oncology, Helse Stavanger HF, 4011 - Stavanger/NO
  • 2 Department Of Neurology, Helse Stavanger HF, 4011 - Stavanger/NO
  • 3 Department Of Oncology And Medical Physics, Helse Bergen HF, 5021 - Bergen/NO
  • 4 Department Neurosurgery, Helse Bergen HF, 5021 - Bergen/NO


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Abstract 355P


Butterfly glioblastoma (bGBM) is a rare and sparsely described subgroup of glioblastoma with a bihemispheric tumour crossing the corpus callosum. bGBM is associated with a dismal prognosis, and optimal treatment remains unclear. We aimed to evaluate overall survival and survival stratified by treatment strategies in a real-world setting.


This was a retrospective population-based study on patients diagnosed with bGBM in Western Norway from 2007 to 2014. Clinical data and treatment strategy were collected from medical records. Treatment modalities included resection, radiation therapy and Temozolomide. Survival analyses were caluclated by Kaplan Meier method and Cox regression.


Among 381 diagnosed with glioblastoma in the study period, we identified 36 patients (9.4%) with bGBM. Sixteen (44.4%) were histologically confirmed and 20 (55.6 %) were diagnosed solely by MRI. Median age was 65.9 years. Median overall survival was 5.9 months (95% CI 2.7-9.2). One-, two, and three-year survival rates were 19.4%, 16.7%, and 8.3%. Median survival in patients receiving best supportive care, one, two, and three treatment modalities was 1.6 months (95% CI 0.5-2.6), 4.5 months (95% CI 3.5-5.5), 7.4 months (95% CI 5.5-9.3), and 7.8 months (95% CI 6.7-8.9) (p<0.001). Further survival analysis in the table. Median survival in patients aged under 70 years was 7.8 months (95% CI 6.3-9.3), compared to 2.1 months (95% CI 0.0-5.0) in patients aged over 70 years (p<0.001). In these two groups, 21 of 23 patients (91.3%) vs two of 13 patients (15.4%) were treated with at least two modalities (p<0.0001). Table: 355P

Multivariate Cox regression analysis for overall survival in 36 patients diagnosed with butterfly glioblastoma between 2001 and 2014

n (%) Adjusted hazard ratio (HR) 95%CI P value
Female 21 (58.3%) 0.53 0.24-1.18 0.12
Age ≥ 70 years 13 (36.1%) 2.35 0.64-8.61 0.20
Primary treatment (including resection, radiation therapy and Temozolomide)
Best supportive care 6 (16.7%) Ref
One modality 7 (19.4%) 0.24 0.07-0.80 0.02
Two modalities 17 (47.2%) 0.13 0.03-0.63 0.01
Three modalities 6 (16.7%) 0.15 0.03-0.86 0.03


Median overall survival was poor, however with a three-year survival rate comparable to that observed in non-butterfly glioblastoma cohorts. Increased treatment intensity was associated with improved survival. Patients with bGBM may benefit from a more aggressive treatment approach despite a dismal prognosis. Few patients aged over 70 years received multimodal treatment and had a significantly inferior outcome.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.


Family Blix Foundation and Svanhild and Arne Must Foundation.


All authors have declared no conflicts of interest.

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