Glioblastoma Multiforme (GBM) is recognized as the most frequently occurring and aggressively malignant tumor within the central nervous system (CNS). Originating from astrocytes, these tumors exhibit rapid growth and infiltrative behavior within brain tissue. GBM can present at any age but shows a higher incidence rate in adults aged over 50. Classified as a Grade IV glioma by the World Health Organization (WHO), GBM is notorious for its poor prognosis and therapeutic challenges. Multidisciplinary treatment models can enhance life expectancy and quality of life.
Classification and Glioblastoma Stages
Glioblastomas are strictly categorized as WHO Grade IV tumors, reflecting their high malignancy and rapid progression. Although formal staging systems are limited, glioblastoma stage 4 and stage 4 glioblastoma terms are commonly used to describe the aggressive nature of the tumor. Types of glioblastoma:
1. Primary Glioblastoma:
Develops de novo from normal glial cells without evidence of a prior low-grade lesion. It is more common in older adults and typically has a poorer prognosis.
2. Secondary Glioblastoma:
Evolves from lower-grade gliomas through malignant transformation. This subtype is more often observed in younger patients (under 45) and usually presents a slightly better prognosis.
These glioblastoma types differ in their genetic profiles, clinical course, and response to treatment.
Causes of Glioblastoma
While the precise glioblastoma causes remain uncertain, factors such as genetic mutations, exposure to ionizing radiation, and environmental influences have been implicated. Research into the molecular and genetic landscape of GBM continues to provide insights that inform diagnosis and personalized treatment.
Clinical Symptoms of Glioblastoma
Symptoms vary depending on tumor size and location, often worsening rapidly as the tumor expands. Common glioblastoma symptoms include:
Severe Headaches: Frequently arise due to the tumor exerting pressure within the skull, leading to elevated intracranial pressure.
Nausea and Vomiting: Related to increased intracranial pressure and brainstem involvement.
Seizures: Caused by disrupted electrical activity in the brain, which may lead to partial or generalized convulsions.
Cognitive Decline: Memory loss, difficulty concentrating, impaired speech, and altered mental status, especially when the frontal lobes are involved.
Motor Weakness: Muscle weakness, loss of coordination, and balance difficulties from involvement of motor pathways.
Visual Disturbances: Lesions near optic tracts may cause double vision, visual field defects, or vision loss.
Diagnostic Approach for Glioblastoma
Accurate diagnosis relies on a combination of neurological examination and advanced imaging modalities:
Neurological Exam: Comprehensive assessment of motor strength, reflexes, sensory function, cognition, and speech.
Magnetic Resonance Imaging (MRI): The diagnostic gold standard in glioblastoma radiology, MRI provides detailed images of tumor size, location, infiltration, necrotic regions, and abnormal vasculature.
Computed Tomography (CT): Used when MRI is contraindicated or unavailable; helpful in detecting calcifications or hemorrhage but less detailed for soft tissue.
Multimodal Treatment Strategies for Glioblastoma
Effective management of GBM requires an integrated, multidisciplinary approach involving surgery, radiation, chemotherapy, and emerging therapies:
1. Surgical Intervention
Microsurgical Resection: The primary treatment step is maximal safe resection to remove as much tumor tissue as possible without compromising neurological function. Due to infiltrative nature, complete resection is often unachievable.
2. Radiotherapy
Adjuvant radiation therapy is applied post-surgery to eliminate residual tumor cells, improving progression-free survival.
3. Chemotherapy
The oral alkylating agent Temozolomide remains the standard chemotherapeutic drug, administered concurrently with radiotherapy and continued as maintenance therapy.
4. Targeted Therapy and Immunotherapy
Bevacizumab: This anti-angiogenic agent is especially employed in recurrent or progressive GBM to reduce tumor vascularization, decrease edema, and alleviate symptoms.
Next-Generation Sequencing (NGS) Testing: Molecular profiling through NGS facilitates identification of actionable mutations, enabling targeted therapy tailored to the tumor’s genetic landscape.
5. Laser Interstitial Thermal Therapy (LITT)
For patients with tumor progression and/or radiation necrosis despite conventional treatment, Laser Interstitial Thermal Therapy (LITT) offers a new treatment for glioblastoma that is minimally invasive. Recently, LITT has shown treatment outcomes comparable to those of traditional methods, indicating its potential to be used as a first-line treatment option. By applying focused laser-induced thermal ablation, it effectively destroys tumor tissue and radiation necrosis areas while precisely sparing the surrounding healthy brain tissue. This method is especially valuable when further surgery or radiation therapy is contraindicated.
How to Prevent Glioblastoma?
Currently, there is no proven way on how to prevent glioblastoma. Avoiding known risk factors like unnecessary radiation exposure and promoting brain health may contribute to general risk reduction. Ongoing research aims to uncover more definitive preventive strategies.
Conclusion
Glioblastoma Multiforme (GBM) is a devastating Grade IV brain tumor, characterized by rapid progression and poor prognosis. Understanding its glioblastoma definition, glioblastoma histology, causes, and clinical course aids in diagnosis and management. The integration of surgery, radiotherapy, chemotherapy, molecular tests and novel treatment methods -Laser Induced Thermal Therapy- represents the current frontier in GBM care. Research into glioblastoma new treatments remains vital to improve survival outcomes for affected patients.
Neuro-oncology tumor boards are multidisciplinary case review meetings where neurosurgeons, oncologists, radiologists, pathologists, and other specialists collaboratively evaluate complex brain tumor cases. These boards ensure that each patient receives a personalized treatment plan based on current clinical evidence and molecular profiling.
Importantly, participation in such multidisciplinary tumor boards has been associated with improved clinical decision-making, prolonged survival, and enhanced quality of life in patients with glioblastoma.