Surgery vs. Biopsy in the Treatment of Butterfly Glioblastoma: A Systematic Review and Meta-Analysis

The Impact of Extensive Surgical Resection of Butterfly Glioblastomas on Outcomes in the Presence of TERT Mutation and EGFR Amplification: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

This study aimed to assess if extensive surgical resection enhances outcomes in wild-type Isocitrate Dehydrogenase (IDH) butterfly glioblastoma (B-GBM) patients, despite the presence of Telomerase Reverse Transcriptase (TERT) mutation and Epidermal Growth Factor Receptor (EGFR) amplification.

METHODS

The study, retrospectively conducted from 2014 to 2022, involved 723 GBM patients, 41 of whom met the criteria for IDH wild-type B-GBM. Exclusion criteria comprised prior diagnoses or treatments for low-grade glial tumors. Surgeons, employing two approaches-partial and extensive surgery-categorized patients based on age, sex, tumor location, corpus callosum involvement, and genetic characteristics. The interval between initial surgery and tumor recurrence/tumor-free period (TR/TFP) and overall survival (OS) were recorded and compared between the partial and extensive resection groups, analyzing the impact of resection width on TR/TFP and OS. Preoperative assessments utilized thin-section cranial computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI). Intraoperatively, tumor excision was guided by sodium fluorescein, and margins were delineated via neuronavigation. Genetic alterations (TERT mutations and EGFR amplifications) were correlated with surgical type, TR/TFP, and OS. Karnofsky Performance Scale (KPS) evaluations were performed pre- and post-operatively and at key intervals, comparing outcomes between surgical groups. Standard radiotherapy and chemotherapy regimens were administered to all patients.

RESULTS

Extensive resection yielded significantly longer TR/TFP compared to partial resection, despite TERT gene mutation and EGFR amplification being linked to shorter TR/TFP and OS. Its impact on OS, however, was not significant. KPS scores indicated a superior quality of life after extensive resection, with sustained improvement upon recurrence.

CONCLUSIONS

Extensive resection of B-GBM, even in the presence of adverse genetic alterations, may prolong TR/TFP, offering patients a period of improved comfort with minimal distress.

Radiological, clinical, and molecular analyses reveal distinct subtypes of butterfly glioblastomas affecting the prognosis

Background

Glioblastoma (GB) is known for its highly invasive nature. Images of butterfly GB (bGB) often illustrate this characteristic, but the molecular background and origins of bGB remain unknown.

Methods

We analyzed a cohort of 34 bGB patients from our dataset (K-cohort) and 46 bGB patients from publicly available datasets, including TCGA-GBM, CPTAC-GBM, IvyGAP, and UPENN-GBM.

Results

In the K-cohort, the median age was 66 years, and molecular analyses revealed TERT promoter mutations in 55.9% of cases, with no cases exhibiting H3F3A, HIST1H3B, or BRAF mutations. Sequential radiological imaging from the K-cohort provided unique insights, showing one case originating in the corpus callosum (CC) and 3 cases originating in the cerebral hemisphere before developing into bGB. Multi-regional sampling supported a mutational trajectory from the hemisphere to the CC. These observations indicate the presence of 2 distinct radiological origins for bGB. Consequently, we classified cases into CC-type and Hemispheric-type based on the tumor volume ratio within the CC. This subgrouping was clinically meaningful; the CC-type is an independent poor prognostic factor for overall survival, with a hazard ratio of 1.8 (95% confidence interval 1.1-3.0, P = .033), and is molecularly distinct by a higher frequency of methylated MGMTp (P = .0039) compared to the Hemispheric-type.

Conclusions

Our results highlight that the radiological features of bGB are not homogenous and can indicate 2 potential subtypes based on their origins. Further studies are mandatory, but CC-type and Hemispheric-type exhibit distinct clinical backgrounds, outcomes, and molecular features.

Bilateral Trans-Sulcal and Interhemispheric Approaches for Butterfly Glioblastoma: 2-Dimensional Operative Video

Butterfly glioblastoma (bGB) poses significant surgical challenges, yet recent findings have highlighted the potential of surgical decompression in extending patient survival.1-10 The selection of a surgical strategy for bGB varies across studies. Generally, the side with a larger tumor volume is a preferred approach route, and the nondominant hemisphere is preferred when both tumors are similar in size. The contralateral tumor is removed via the resection cavity of the ipsilateral side,11 with successful utilization of endoscopic-assisted techniques.8 In the case of deep-seated bGB covered with a thick intact brain, accessing the tumor requires creating an invasive corridor, therefore minimizing the damage to the intact brain is ideal. A man in his 70s presented the new-onset seizure. Preoperatively, the patient exhibited a Karnofsky performance status of 50% without any motor deficits, and magnetic resonance imaging demonstrated a deep-seated anterior bGB with a larger tumor volume on the left dominant side. Imaging showed the tumor located just beneath the bilateral superior frontal sulci. Therefore we used these sulci to access the tumor with the minimum cut of the intact brain while preserving the frontal aslant tracts and used bilateral interhemispheric approaches to protect the cingulate bundles. We conducted the same technique for another deep-seated anterior bGB case, both resulting in postoperative Karnofsky performance status improvements (Video 1). Tailoring the surgical approach to the unique characteristics of each bGB case is important. The patients consented to the procedure and the publication of their images.

Bilateral Laser Interstitial Thermal Therapy for Butterfly Gliomas Compared With Needle Biopsy: A Preliminary Survival Study

BACKGROUND AND OBJECTIVES

Bilateral/butterfly glioblastoma (bGBM) has a poor prognosis. Resection of these tumors is limited due to severe comorbidities that arise from surgical procedures. Laser interstitial thermal therapy (LITT) offers a minimally invasive cytoreductive therapy for deep-seated tumors such as bGBM. The objective of this study was to evaluate the safety of bilateral LITT in patients with bGBM.

METHODS

Medical records of all consecutive patients diagnosed with bGBM by a single surgeon at a single institution from January 2014 to August 2022 were reviewed. Clinical, safety, and radiographic volumetric data were obtained. In addition, an exploratory analysis of survival was performed.

RESULTS

A total of 25 patients were included; 14 underwent biopsy only, and 11 underwent biopsy + LITT (7 underwent bilateral and 4 underwent unilateral LITT). No (0%) intraoperative or postoperative complications were recorded in the treatment group. Tumor volume negatively correlated with extent of treatment (r 2 = 0.44, P = .027). The median progression-free survival was 2.8 months in the biopsy-only group and 5.5 months in the biopsy + LITT group ( P = .026). The median overall survival was 4.3 months in the biopsy-only group and 10.3 months in the biopsy + LITT group ( P = .035).

CONCLUSION

Bilateral LITT for bGBM can be safely performed and shows early improvement of the progression-free survival and long-term survival outcomes of these patients.

A Case Series of Surgical Resection of Anterior and Posterior Butterfly Glioma Grade 4 via a Minimally Invasive Keyhole Approach

Surgical resection of infiltrating glial neoplasms has proven to improve quality of life and confer a significant survival benefit. As accumulating evidence cements the role of surgery in grade 4 gliomas, there is a general trend to transition away from traditional large craniotomies to smaller 'keyhole' approaches, which aim to reduce the trauma and complication profiles associated with large exposures. A keyhole approach uses a small craniotomy positioned perfectly to reach at least all the target structures that a conventional approach would reach. We present a case series of operated butterfly gliomas grade 4 patients through keyhole approaches. All three operated patients have better survival than the literature biopsy groups. The resection of butterfly gliomas should be considered in selected cases. For some patients, it is feasible with the technology used nowadays, with improved quality of life and better survival prognosis.

Visualising spatial heterogeneity in glioblastoma using imaging habitats

Glioblastoma is a high-grade aggressive neoplasm characterised by significant intra-tumoral spatial heterogeneity. Personalising therapy for this tumour requires non-invasive tools to visualise its heterogeneity to monitor treatment response on a regional level. To date, efforts to characterise glioblastoma's imaging features and heterogeneity have focussed on individual imaging biomarkers, or high-throughput radiomic approaches that consider a vast number of imaging variables across the tumour as a whole. Habitat imaging is a novel approach to cancer imaging that identifies tumour regions or 'habitats' based on shared imaging characteristics, usually defined using multiple imaging biomarkers. Habitat imaging reflects the evolution of imaging biomarkers and offers spatially preserved assessment of tumour physiological processes such perfusion and cellularity. This allows for regional assessment of treatment response to facilitate personalised therapy. In this review, we explore different methodologies to derive imaging habitats in glioblastoma, strategies to overcome its technical challenges, contrast experiences to other cancers, and describe potential clinical applications.

Combination of asleep and awake craniotomy as a novel strategy for resection in patients with butterfly glioblastoma: Two case reports

Background:

Several studies have reported that gross total resection contributes to improved prognosis in patients with butterfly glioblastoma (bGBM). However, it sometimes damages the corpus callosum and cingulate gyrus, leading to severe neurological complications.

Case Description:

We report two cases of bGBM that was safely and maximally resected using brief and exact awake mapping after general anesthesia. Two patients had butterfly tumors in both the frontal lobes and the genu of the corpus callosum. Tumor resection was first performed on the nondominant side under general anesthesia to shorten the resection time and maintain patient concentration during awake surgery. After that, awake surgery was performed for the lesions in the dominant frontal lobe and genu of the corpus callosum. Tumor resection was performed through minimal cortical incisions in both frontal lobes. Postoperative magnetic resonance imaging showed gross total resection, and the patients had no chronic neurological sequelae, such as akinetic mutism and abulia.

Conclusion:

bGBM could be safely and maximally resected by a combination of asleep and brief awake resection, which enabled patients to maintain their attention to the task without fatigue, somnolence, or decreased attention. The bilateral approach from a small corticotomy can avoid extensive damage to the cingulate gyrus.