Glioblastoma: Diagnosis, Stupp Protocol, and Treatment Options

Glioblastoma, historically termed glioblastoma multiforme (GBM), is a fast-growing malignant neoplasm originating from glial precursor cells within the central nervous system. In a healthy brain, glial cells—specifically astrocytes—serve vital supportive, nutritional, and protective functions for neurons. In glioblastoma, genetic alterations disrupt normal cellular controls, prompting uncontrolled cell proliferation, extensive local tissue infiltration, and the formation of abnormal, fragile blood vessels.

According to the 2021 World Health Organisation (WHO) Classification of Tumours of the Central Nervous System, glioblastoma is formally defined as an astrocytic glioma that is IDH-wildtype (meaning it lacks mutations in the isocitrate dehydrogenase genes) and designated as CNS WHO grade 4. Even if a diffuse astrocytoma appears microscopically less aggressive, the presence of specific genetic hallmarks—such as TERT promoter mutations, EGFR gene amplification, or combined chromosome 7 gain and chromosome 10 loss (+7/-10)—now mandates a diagnosis of glioblastoma, grade 4. This updated biological classification reflects our modern understanding that genetic drivers dictate tumour behaviour far more reliably than microscopic appearance alone.

Unlike cancers that develop in organs such as the breast, lung, or colon, glioblastoma almost never metastasises to distant organs outside the brain and spinal cord. However, it exhibits a deeply infiltrative growth pattern. Microscopic tumour cells migrate along white-matter tracts and blood vessels far beyond the visible borders seen on standard radiological scans. Because these cells interlace with healthy, functional brain tissue, complete surgical eradication is biologically impossible, which is why glioblastoma is managed as a chronic, aggressive condition requiring multifaceted treatment.

For you and your loved ones, a glioblastoma diagnosis marks the beginning of an intensive clinical pathway that requires careful coordination, open communication, and sustained emotional resilience. It means you will be supported by a dedicated multidisciplinary team (MDT), including neurosurgeons, clinical oncologists, neuroradiologists, neuropathologists, clinical nurse specialists, and neuro-rehabilitation therapists. Each decision—from the surgical approach to the timing of radiotherapy and chemotherapy—is tailored to balance effective disease control with the preservation of your cognitive and physical independence.

In practical terms, life following a diagnosis involves navigating regular hospital attendances, taking daily medications, and managing treatment-related fatigue. It also involves practical adaptations, such as temporarily pausing driving in accordance with national safety regulations and accessing neuro-physiotherapy or speech therapy when needed. While the diagnosis is serious, focusing on each treatment phase sequentially, maintaining honest dialogues with your clinical team, and leaning on specialist palliative and supportive care services early can bring meaningful stability and empower you to live each day as fully as possible.

The symptoms of glioblastoma vary depending on the tumour's anatomical location within the brain, its rate of growth, and the severity of surrounding tissue swelling. Most symptoms fall into two broad categories: generalised symptoms resulting from elevated intracranial pressure, and focal deficits caused by localized compression or irritation of specific functional brain regions.

Increased intracranial pressure frequently manifests as a persistent, dull headache that differs from ordinary tension headaches or migraines. These headaches are characteristically worse upon waking in the morning, may be accompanied by nausea or unprovoked vomiting, and often intensify during activities that temporarily increase pressure inside the skull, such as coughing, straining, or bending forward. New-onset seizures are another common and distressing presentation, occurring in roughly 25% to 40% of patients. Seizures can be generalised (convulsive tonic-clonic episodes) or focal, manifesting subtly as brief sensory alterations, involuntary muscle twitching, unusual tastes or smells, or transient lapses in awareness.

Focal symptoms reflect the specialised job of the affected brain lobe. Tumours in the frontal lobe may cause subtle personality changes, apathy, disinhibition, executive dysfunction, or weakness down one side of the body (hemiparesis). A mass in the temporal lobe often impairs memory processing or speech comprehension, whereas parietal lobe involvement can trigger sensory loss, difficulty processing spatial information, or reading and writing problems. Occipital tumours typically produce visual field deficits, such as hemianopia (loss of half the field of vision). Any new, unexplained neurological deficit, sudden cognitive decline, or first-time seizure warrants urgent clinical evaluation and brain imaging.

At the cellular level, glioblastoma develops through the sequential accumulation of genetic and epigenetic alterations that disable essential tumour-suppressor networks and constitutively activate growth-promoting signalling cascades. Normal astrocytes and neural stem cells possess tightly regulated internal switches that control when cells grow, divide, and die. In glioblastoma, mutations in key biological pathways—such as the RTK/RAS/PI3K pathway (often through EGFR alterations), the p53 pathway, and the retinoblastoma (Rb) pathway—allow abnormal cells to escape programmed cell death (apoptosis) and multiply without restraint.

Despite widespread scientific investigation, the initial trigger for these spontaneous genetic mutations remains unknown in the vast majority of cases. Glioblastoma is not caused by lifestyle factors such as diet, stress, alcohol consumption, smoking, or minor head trauma sustained earlier in life. Furthermore, extensive global epidemiological studies have found no credible, reproducible link between brain tumour risk and the use of cellular telephones or non-ionising electromagnetic fields. In short, glioblastoma arises spontaneously through complex, internal biological errors that could not have been prevented through personal lifestyle modifications.

The only definitively proven environmental risk factor for glioblastoma is prior exposure to high doses of therapeutic ionising radiation directed at the head or neck, usually administered decades earlier to treat childhood malignancies such as leukaemia or medulloblastoma. Even so, radiation-induced gliomas account for only a tiny fraction of total cases encountered in clinical practice.

Demographic trends show that glioblastoma is slightly more prevalent in men than in women (approximately 1.6 times more common) and predominantly affects older adults, with the median age of diagnosis falling between 60 and 65 years. An extremely small proportion of cases (under 5%) occur as part of rare hereditary cancer predisposition syndromes, such as Li-Fraumeni syndrome (associated with inherited TP53 mutations), Lynch syndrome, or neurofibromatosis type 1. Because the vast majority of cases are completely sporadic and lack identifiable external triggers, there are currently no established screening tests or lifestyle interventions that can reliably prevent glioblastoma.

The diagnostic pathway typically begins in an emergency department or neurology clinic following a first seizure or progressive neurological symptoms. The initial diagnostic imaging study is usually a computed tomography (CT) scan of the brain, which can rapidly identify a space-occupying lesion, intracranial haemorrhage, or severe mass effect. However, magnetic resonance imaging (MRI) of the brain, performed both with and without intravenous gadolinium contrast, is the definitive and indispensable radiological investigation.

On a contrast-enhanced T1-weighted MRI, glioblastoma characteristically appears as a heterogeneous, thick, irregularly ring-enhancing mass enclosing a central, dark core of hypointense, dead tissue (necrosis). Surrounding this active tumour rim is an extensive zone of hyperintensity visible on T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences, representing vasogenic oedema interspersed with non-enhancing, infiltrative tumour cells. Advanced imaging modalities—such as magnetic resonance spectroscopy (MRS), perfusion-weighted imaging (which measures local cerebral blood volume to detect neoangiogenesis), and functional MRI (fMRI) or diffusion tensor tractography (to map language and motor pathways)—are frequently employed to evaluate the tumour's metabolic profile and map its spatial relationship to essential, eloquent brain structures.

While radiological characteristics are often highly suggestive of high-grade glioma, a formal, definitive diagnosis cannot be established from scans alone. Tissue acquisition via stereotactic needle biopsy or open surgical craniotomy is mandatory. A specialist neuropathologist evaluates the biopsy tissue using histological staining, immunohistochemistry, and molecular genetic assays to establish the precise diagnosis in accordance with modern international criteria.

Unlike carcinomas originating in the lungs, breasts, or bowel, primary brain tumours such as glioblastoma are not categorised using the classical TNM (Tumour, Node, Metastasis) staging system. Because the brain lacks traditional lymphatic drainage and circulating glioma cells rarely establish colonies in non-neural organs, stage I through IV systemic designations do not apply.

Instead, neuro-oncologists use the World Health Organisation (WHO) histological and molecular grading system to determine the tumour's biological aggressiveness, ranging from Grade 1 (slow-growing, circumscribed tumours often curable by surgery alone) to Grade 4 (rapidly proliferating, highly malignant, and widely infiltrative neoplasms). Glioblastoma is, by definition, a Grade 4 tumour—the highest grade recognized in neuro-oncology. Grade 4 status signifies that the tumour exhibits rapid cellular turnover, the formation of new, abnormal microvasculature, and areas of tissue necrosis.

Rather than assessing anatomical spread to other organs, clinical assessment in glioblastoma focuses on the patient’s functional performance status, measured by scales such as the Karnofsky Performance Scale (KPS) or Eastern Cooperative Oncology Group (ECOG) score. Performance status, patient age, tumour location in relation to eloquent brain areas, and the extent of surgical resection achievable serve as the practical clinical indicators used to guide treatment intensity and prognostic evaluations.

Contemporary neuropathology relies on sophisticated molecular and genetic testing to fully characterise glioblastoma. Following tissue extraction during surgery, specimens undergo extensive laboratory analysis that combines traditional light microscopy with advanced genomic techniques, such as next-generation sequencing (NGS), pyrosequencing, and fluorescence in situ hybridisation (FISH).

The first critical assessment is confirming isocitrate dehydrogenase (IDH) status. The vast majority of glioblastomas are IDH-wildtype, meaning they carry normal IDH1 and IDH2 genes. The detection of a mutant IDH gene excludes the formal diagnosis of glioblastoma under current guidelines, reclassifying the tumour as an astrocytoma, IDH-mutant (which carries a generally more favourable prognosis). Additionally, pathologists test for hallmark molecular signatures such as TERT promoter mutations, EGFR amplification, and the simultaneous gain of chromosome 7 and loss of chromosome 10, all of which confirm Grade 4 biological behaviour even when tissue specimens appear deceptively low-grade under the microscope.

The most clinically consequential molecular biomarker in glioblastoma is the methylation status of the O-6-methylguanine-DNA methyltransferase (MGMT) gene promoter. MGMT is a cellular DNA repair enzyme. When its promoter region is methylated (epigenetically switched off), the tumour cell cannot readily repair the DNA damage inflicted by alkylating chemotherapy drugs such as temozolomide. Patients whose tumours demonstrate MGMT promoter methylation derive substantially greater clinical benefit from temozolomide chemotherapy, making this test an essential component of clinical treatment planning.

Glioblastoma belongs to the broader family of adult-type diffuse gliomas, which represent the most common primary intra-axial neoplasms of the central nervous system. Under the current 2021 WHO diagnostic classification, adult diffuse gliomas are categorised into three distinct clinicopathological and genetic entities: Astrocytoma, IDH-mutant (which can be graded as CNS WHO grade 2, 3, or 4); Oligodendroglioma, IDH-mutant and 1p/19q-codeleted (CNS WHO grade 2 or 3); and Glioblastoma, IDH-wildtype (CNS WHO grade 4).

Differentiating these tumour types is critical because their natural biological histories and responses to therapy diverge dramatically. For instance, an IDH-mutant astrocytoma—even when exhibiting aggressive features that warrant a grade 4 designation—carries a substantially better median survival and more protracted disease course than an IDH-wildtype glioblastoma. Similarly, oligodendrogliomas bearing the diagnostic 1p/19q co-deletion are exceptionally chemosensitive. Other high-grade tumours of the central nervous system that can share clinical or radiological similarities include diffuse midline gliomas (characterised by H3 K27 alterations, often arising in younger patients and involving deep brain structures like the thalamus or brainstem) and secondary central nervous system lymphomas. Precise molecular diagnostics ensure that every patient is treated under the protocol strictly validated for their tumour's biological subtype.

The standard of care for newly diagnosed glioblastoma follows a well-established, multimodal paradigm designed to maximise local disease control while safeguarding neurological capability and quality of life. The initial therapeutic cornerstone is maximal safe surgical resection. Whenever feasible, a neurosurgeon performs a craniotomy to remove as much visible, enhancing tumour mass as possible. Because glioblastoma frequently abuts or infiltrates eloquent brain regions responsible for speech, movement, or vision, modern neurosurgery leverages sophisticated technologies. These include intraoperative neuronavigation (frameless stereotaxy), intraoperative MRI, awake cortical and subcortical brain mapping, and fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA). 5-ALA causes malignant glioma cells to fluoresce bright pink under violet-blue light, enabling the surgeon to distinguish tumour tissue from adjacent healthy cortex in real time, thereby improving resection completeness while lowering neurological complication risks.

Following surgical recovery (typically within three to six weeks), patients who maintain a robust performance status proceed to adjuvant chemoradiotherapy under the internationally recognized Stupp protocol. This standard regimen begins with focal external-beam radiotherapy, delivered using highly conformal techniques such as intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT). The radiation course generally totals 60 Gray (Gy), administered in 30 daily fractions over six weeks. Throughout these six weeks of radiation, patients ingest oral temozolomide (TMZ) daily at a dose of 75 mg per square metre of body surface area. Temozolomide functions as a radiosensitiser, making residual microscopic tumour cells more vulnerable to radiation-induced DNA strand breaks.

Upon completing concurrent chemoradiotherapy, patients take a four-week rest period before commencing the maintenance phase of the Stupp protocol. This entails up to six monthly cycles of adjuvant temozolomide, administered orally at higher doses (150 to 200 mg per square metre) for five consecutive days out of every 28-day cycle. An established non-invasive adjunct during this maintenance window is Tumour Treating Fields (TTFields). Delivered via a portable medical device connected to adhesive ceramic transducer arrays placed directly on the shaved scalp, TTFields generates low-intensity, intermediate-frequency (200 kHz) alternating electric fields. These fields physically disrupt the alignment of charged mitotic proteins during cancer cell division, triggering cellular apoptosis. Clinical trial data show that adding TTFields to maintenance temozolomide significantly extends both progression-free and overall survival compared to temozolomide alone.

Inevitably, glioblastoma recurs due to microscopic infiltration beyond the treated field and intrinsic or acquired therapy resistance. When tumour progression is detected, management is individualized based on previous treatment response, current functional status, time elapsed since initial therapy, and the anatomical distribution of the recurrence. Secondary therapeutic options include re-resection (if safely feasible), stereotactic re-irradiation in carefully selected patients, second-line systemic chemotherapies such as lomustine (CCNU) or carboplatin, and the anti-angiogenic monoclonal antibody bevacizumab, which neutralises vascular endothelial growth factor (VEGF) to reduce peritumoural oedema and alleviate debilitating neurological symptoms.

Clinical trials represent a crucial treatment consideration at every stage of the disease, from initial diagnosis through to recurrence. Given the limitations of current standard options, clinical trials provide access to innovative strategies, including targeted molecular therapies directed against specific receptor mutations, oncolytic viral therapies, personalised dendritic cell vaccines, immune-checkpoint modulators, antibody-drug conjugates, and novel radiosensitising agents. Patients and families are strongly encouraged to discuss open trial protocols with their neuro-oncology team early in their care journey.

Discussing survival figures for glioblastoma requires both medical honesty and deep clinical compassion. Published statistics represent historical population averages drawn from large clinical cohorts; they cannot predict the exact disease course or personal outcome for any individual patient. Historically, across broad unselected populations receiving modern standard multimodal therapy (maximal safe resection, concurrent radiotherapy and temozolomide, and adjuvant maintenance), median overall survival ranges from roughly 14 to 20 months, with approximately 25% to 33% of patients surviving to two years, and a smaller subset (roughly 5% to 10%) surviving beyond five years.

An individual's prognosis is heavily influenced by multiple clinical and biological variables rather than the diagnosis alone. Favourable prognostic factors include a younger age at diagnosis (particularly under 50 years), a high baseline functional status (a high Karnofsky Performance Scale score, reflecting physical independence), the achievement of complete gross total resection of the contrast-enhancing tumour volume, and, crucially, a methylated MGMT promoter status. Patients with MGMT-methylated tumours consistently exhibit significantly longer progression-free and overall survival due to their heightened biological sensitivity to temozolomide. Neuro-oncology teams continuously refine supportive care, symptom control, and rehabilitation to help each person sustain the best possible functional life throughout their treatment course.