Abstract 355P
Background
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.
Methods
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.
Results
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 |
Conclusions
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.
Funding
Family Blix Foundation and Svanhild and Arne Must Foundation.
Disclosure
All authors have declared no conflicts of interest.