What Is a Glioma?
A glioma is a primary tumor of the central nervous system that begins in glial cells, the support network of the brain and spinal cord. Unlike meningiomas, which usually push on the brain from outside, many gliomas grow within the brain tissue itself and can blend into normal brain pathways.
This infiltrative behavior is why glioma treatment is different from many other brain tumors. Surgery is crucial, but the aim is maximal safe resection: remove as much tumor as possible while preserving speech, movement, memory, vision, personality and independence.
A glioma diagnosis is no longer based only on what cells look like under a microscope. Today, the integrated diagnosis combines tumor type, WHO grade and molecular features such as IDH mutation, 1p/19q codeletion, ATRX, TERT, CDKN2A/B and MGMT status.
Types of Glioma
Diffuse glioma with astrocytic features and IDH mutation. Grades range from 2 to 4. Treatment often includes surgery, radiation and chemotherapy depending on grade, age, symptoms and residual tumor.
Often seizure-presenting and relatively treatment-sensitive. Many patients live for years with careful surgery and appropriately timed radiation/chemotherapy.
Usually grows rapidly and requires maximal safe surgery followed by radiation with temozolomide, often with tumor treating fields and clinical trial consideration.
Pilocytic astrocytoma, ganglioglioma and other circumscribed tumors may behave very differently from adult diffuse gliomas. Some can be cured with complete removal.
| WHO Grade | Meaning | Treatment Implication |
|---|---|---|
| Grade 1 | Circumscribed, often slow-growing | Complete surgery may be curative in selected tumors. |
| Grade 2 | Diffuse, lower-grade but infiltrative | Surgery plus surveillance or adjuvant treatment depending on risk. |
| Grade 3 | Malignant, actively growing | Surgery plus radiation and chemotherapy commonly recommended. |
| Grade 4 | Most aggressive biology | Requires combined treatment and close follow-up. |
Symptoms: How Gliomas Present
Symptoms depend more on location and growth speed than on the name of the tumor. A slow frontal glioma may cause subtle personality change, while a small tumor near the motor strip may cause seizures or weakness.
A first seizure in an adult is a common presentation, especially with lower-grade gliomas.
Motor or sensory cortex involvement can cause arm, leg or facial symptoms.
Word-finding difficulty, slurred speech or comprehension problems may occur with dominant hemisphere tumors.
Frontal or temporal tumors may cause apathy, irritability, confusion or executive dysfunction.
Visual field loss, double vision or difficulty reading may occur depending on pathway involvement.
Rapidly growing tumors can cause headache, vomiting, drowsiness or raised intracranial pressure.
New seizure, rapidly worsening weakness, severe headache with vomiting, drowsiness, confusion, sudden speech difficulty or major vision loss requires prompt medical evaluation.
Diagnosis: MRI, Mapping and Tissue
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MRI Brain with Contrast - Shows tumor location, enhancement, edema, mass effect, necrosis, non-enhancing infiltrative component and relation to eloquent brain.
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Advanced MRI - Perfusion, spectroscopy, diffusion, functional MRI and DTI tractography can help estimate grade and plan safer surgery near speech, motor and white matter pathways.
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Surgery or Biopsy for Tissue - Tissue is required for definitive diagnosis and molecular testing. Biopsy may be chosen when safe removal is not possible.
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Integrated Pathology - The final report combines histology with molecular markers to define tumor type, grade, prognosis and treatment plan.
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Multidisciplinary Tumor Board - Neurosurgery, neuropathology, radiation oncology, medical oncology, neuroradiology and rehabilitation teams should review complex cases.
MRI can strongly suggest glioma, but treatment decisions increasingly depend on molecular pathology. Two tumors that look similar on MRI can need different treatment because their IDH, 1p/19q and MGMT status differ.
Molecular Markers Patients Should Know
| Marker | What It Means | Why It Matters |
|---|---|---|
| IDH mutation | A defining marker for many adult diffuse gliomas | IDH-mutant tumors usually behave differently and often have better prognosis than IDH-wildtype glioblastoma. |
| 1p/19q codeletion | Defines oligodendroglioma when paired with IDH mutation | Predicts treatment sensitivity and long-term disease course. |
| MGMT promoter methylation | A DNA repair marker | Helps predict benefit from temozolomide chemotherapy, especially in glioblastoma. |
| ATRX / TP53 / TERT / EGFR | Additional molecular features | Help classify tumor lineage and biological behavior. |
| CDKN2A/B loss | High-risk molecular alteration in some IDH-mutant tumors | Can upgrade risk and influence treatment intensity. |
Glioma Surgery: Maximal Safe Resection
Surgery has several goals: relieve pressure, reduce tumor burden, improve seizure control, obtain tissue, and make radiation and chemotherapy more effective. For many gliomas, greater safe removal is associated with better control, but function must come first.
Used when tumors lie near language, calculation, memory or higher cognitive networks. The patient is comfortable but awake during mapping so the surgeon can preserve essential function.
Direct cortical and subcortical stimulation, motor evoked potentials and tractography help protect motor pathways.
5-ALA fluorescence, intraoperative ultrasound, neuronavigation and intraoperative MRI in selected centres help guide resection.
For brainstem, thalamic, multifocal or medically high-risk tumors, stereotactic biopsy may be safer than open resection.
Risks to Discuss
Risks include seizure, bleeding, stroke, infection, swelling, weakness, speech or memory change, visual field loss, CSF leak, incomplete resection, recurrence and anaesthesia complications. The exact risks depend on location.
Radiation, Chemotherapy and TTFields
Most grade 3 and 4 gliomas, and many higher-risk grade 2 gliomas, need treatment beyond surgery. The plan depends on diagnosis, age, performance status, symptoms, residual tumor and molecular profile.
| Treatment | Role | Typical Use |
|---|---|---|
| Radiation therapy | Targets residual microscopic tumor cells | Common after surgery for high-grade glioma and selected lower-grade tumors. |
| Temozolomide | Oral chemotherapy | Standard with and after radiation for glioblastoma; use guided partly by MGMT status. |
| PCV chemotherapy | Procarbazine, lomustine and vincristine | Often considered for oligodendroglioma and selected lower-grade gliomas. |
| Tumor Treating Fields | Wearable electrical field therapy | Used in selected glioblastoma patients alongside maintenance therapy. |
| Targeted therapy / trials | Precision or experimental treatments | IDH inhibitors, vaccines, immunotherapy, viral therapy and trial options may be discussed. |
There is no single glioma protocol for every patient. The same MRI appearance can lead to different recommendations after molecular testing.
Advanced Care and Recurrence Planning
Glioma care is a long-term process. MRI changes after treatment can represent recurrence, treatment effect, radiation necrosis or pseudoprogression, so expert neuroradiology review matters.
Regular MRI tracks residual tumor, treatment response and recurrence.
Trials may provide access to vaccines, targeted therapies, immunotherapy or novel delivery techniques.
May be useful for accessible recurrence causing symptoms or when new tissue is needed.
Seizure care, steroids, cognition support, physiotherapy, speech therapy and psychological care are part of treatment.
Recovery, Rehabilitation and Quality of Life
After Surgery
Recovery depends on tumor location, preoperative symptoms, extent of surgery and brain swelling. Some patients go home in days; others need rehabilitation. Fatigue is common and can last weeks.
Seizure Management
Anti-seizure medication is often needed, especially if seizures occurred before diagnosis. Driving restrictions depend on local law and seizure control.
Rehabilitation
Physiotherapy, occupational therapy, speech therapy, neuropsychology and counseling can help restore independence and adapt to changes in cognition, language, movement or energy.
Watch: Glioma Surgery and Brain Mapping Explained
Use this video section for patient-friendly explanations of glioma, awake craniotomy, brain mapping, radiation and chemotherapy decisions.
Watch on YouTube โQuestions to Ask Your Neuro-Oncology Team
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What is my integrated diagnosis? - Ask for tumor type, WHO grade and molecular markers, not just "glioma."
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Is the tumor near speech, movement, vision, memory or personality networks? - This determines mapping strategy and risk.
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Is maximal safe resection possible, or is biopsy safer? - The safest operation depends on location and goals.
- 4
Will awake mapping, DTI, fMRI, 5-ALA or intraoperative imaging be used? - Ask which tools matter for your tumor.
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What do IDH, 1p/19q and MGMT results mean for me? - These markers shape prognosis and treatment.
- 6
What is the radiation and chemotherapy plan? - Clarify timing, duration, expected benefits and side effects.
- 7
Are clinical trials appropriate now or at recurrence? - Trial timing matters, especially before starting standard treatment.
Glioma treatment is complex and time-sensitive. A second opinion from a high-volume brain tumor centre can clarify surgical strategy, molecular testing, trial eligibility and the balance between tumor control and neurological function.
