The utility of surgery in butterfly glioblastoma: A case-control study.

e13529 Background: Glioblastoma is the most common primary brain tumour and may rarely infiltrate the corpus callosum. Such ‘butterfly’ glioblastomas (BGBM) are believed to confer a poorer prognosis than their non-callosal counterparts. We aimed to determine the impact of surgery on overall survival (OS) and postoperative morbidity in butterfly glioblastomas. Methods: Retrospective analysis was performed on all case notes of patients histologically diagnosed with GBM from January 2011 to January 2017 at The Walton Centre NHS Foundation Trust, Liverpool. Data was collected under the following headings: demographics, tumour characteristics, surgical data, adjuvant therapy and survival data. A case-matched control group was produced according to age, sex and 1o resection. Univariate analysis was performed. Results: 632 glioblastoma patients were identified. 37 patients were diagnosed with butterfly BGBM, with a median age of 62.7 years and a gender split of 24 males (64.9%) to 13 females (35.1%). Median tumour volume was 31700mm3, with 24 (56%) tumours involving the genu and 13 (22%) the splenium of the callosum. Kaplan-Meier analysis with log-rank testing demonstrated a significant (p = 0.04) decrease in median OS in those with BGBM (100 days (95%CI 57-142)) vs controls (276 days (95%CI 224-327)). Resection of BGBMs resulted in longer median OS than biopsy alone (296 days (95%CI 229-363) vs 81 (66-96)), though this was a non-significant difference (p = 0.36). Multifocal disease occurred significantly more often in BGBM patients (p = 0.01), the exclusion of which from analysis demonstrated a significant survival benefit with resection (427 days (95%CI 207-647)) compared to biopsy (221 days (95%CI 151-291)) (p = 0.04). Postoperative complications did not occur significantly more often in BGBM resections than controls (7/36 (19.4%) vs 5/36 (13.9%) (p = 0.257)). Conclusions: Overall, butterfly glioblastomas confer a worse prognosis than those without callosal involvement. A greater prevalence of multifocal disease is seen in butterfly glioblastoma, warranting further investigation. Resection offers a significant improvement in OS in solitary butterfly glioblastomas without a significant increase in postoperative morbidity, and should therefore be considered an efficacious and safe treatment option.