Glioblastoma (GBM)

Glioblastoma (GBM) — now formally called Glioblastoma, IDH-wildtype, WHO Grade 4 — is the most common and most aggressive primary malignant brain tumor in adults. It arises from astrocyte-lineage glial cells and is characterized by rapid infiltrative growth throughout the brain, central necrosis visible on MRI, and a propensity to recur after treatment. GBM is defined not just by histology but by specific molecular features — IDH-wildtype status plus at least one of: EGFR amplification, TERT promoter mutation, or chromosome 7 gain combined with chromosome 10 loss.

The 2021 WHO CNS Tumor Classification made an important distinction: what was previously called 'secondary GBM' — arising in younger patients from progression of a lower-grade tumor — is now classified separately as IDH-mutant Grade 4 astrocytoma. This entity has a significantly more favorable prognosis than IDH-wildtype GBM and has distinct treatment targets (IDH inhibitors). Knowing which type you have — IDH-wildtype GBM or IDH-mutant Grade 4 astrocytoma — is essential information.

MGMT (O6-methylguanine-DNA methyltransferase) is a DNA repair enzyme. Temozolomide — the standard chemotherapy for GBM — works by adding an alkyl group to the DNA of cancer cells, causing their death. MGMT repairs this damage. When the MGMT gene's promoter region is methylated (chemically silenced), the MGMT repair enzyme is not produced — meaning the cancer cells cannot repair the TMZ-induced damage, making them significantly more vulnerable to the drug.

MGMT promoter methylation is present in approximately 40–50% of IDH-wildtype GBM and is the most important predictive biomarker in the disease. Patients with MGMT-methylated GBM respond better to temozolomide and have meaningfully longer survival with the standard Stupp protocol. Patients with MGMT-unmethylated GBM derive less benefit from TMZ, making them priority candidates for alternative approaches, clinical trials, or regimens that do not depend on TMZ as the primary chemotherapy. MGMT testing should be performed on every GBM tissue sample before treatment planning is finalized.

The current standard treatment for newly diagnosed GBM in patients with adequate performance status is the Stupp protocol, now augmented by tumor treating fields (TTFields). It proceeds in phases: First, maximal safe surgical resection — removing as much of the contrast-enhancing tumor as safely possible. Second, concurrent chemoradiation — radiation to 60 Gy over 30 fractions with daily oral temozolomide (75 mg/m²) over 6 weeks. Third, initiation of tumor treating fields (Optune device) to be worn ≥18 hours/day. Fourth, maintenance temozolomide — 150–200 mg/m² on days 1–5 of each 28-day cycle for 6 cycles — continued alongside TTFields.

The EF-14 trial demonstrated that adding TTFields to maintenance TMZ significantly improved overall survival compared to TMZ alone. This makes TTFields a standard component of newly diagnosed GBM treatment — though access varies by country and healthcare system. For elderly patients or those with poor performance status, modified approaches (hypofractionated radiotherapy, TMZ alone, or best supportive care) are tailored to the individual clinical situation.

Tumor treating fields (TTFields) — delivered via the Optune device — is a non-invasive physical treatment that uses alternating electric fields at intermediate frequency (200 kHz for GBM) applied to the scalp through adhesive transducer arrays. The alternating electric fields interfere with the formation of the mitotic spindle — the structure that separates chromosomes during cell division — specifically in rapidly dividing cells. This disrupts tumor cell mitosis and induces death specifically in dividing cancer cells while largely sparing non-dividing normal brain cells.

The EF-14 randomized trial demonstrated that adding TTFields to maintenance temozolomide improved median overall survival compared to TMZ alone — the most significant survival benefit added to standard GBM treatment since the original Stupp protocol. TTFields requires the patient to wear the device for at least 18 hours per day — device compliance is directly correlated with the magnitude of benefit. The device involves shaving the scalp regularly (for array attachment) and following a skin care routine to manage local scalp irritation. TTFields access varies by country, and CancerFax can assist in navigating device access internationally.

Pseudoprogression is a treatment-related MRI phenomenon — an increase in the contrast-enhancing area on post-treatment MRI that resembles tumor growth but actually represents an inflammatory reaction to the recent chemoradiation. It occurs in approximately 20–30% of GBM patients, typically within the first 12 weeks after completing chemoradiation, and is more common in MGMT-methylated tumors. Crucially, pseudoprogression does not represent treatment failure — it often indicates a good treatment response, and continuing the planned maintenance therapy is appropriate.

True tumor progression, by contrast, represents genuine tumor growth and requires a change in treatment approach. Distinguishing pseudoprogression from true progression can be very challenging on standard MRI alone. Advanced MRI techniques — perfusion imaging, MR spectroscopy — and FDG-PET provide additional information. In ambiguous cases, a period of clinical observation (4–8 weeks) with repeat imaging may be more appropriate than immediately switching to second-line therapy based on a single equivocal scan. This distinction should be made at a specialist neuro-oncology center with experience in post-treatment GBM imaging interpretation.

Almost all GBM eventually recurs — the median time to progression with standard treatment is approximately 6–9 months. At recurrence, the options depend on the patient's functional status, the extent and location of recurrence, and the molecular profile of the recurrent tumor. Options include: re-resection (if the recurrence is surgically accessible and the patient's status permits), which is associated with modest benefit in selected patients; bevacizumab (anti-VEGF antibody), which reduces edema and improves radiographic response but has not demonstrated overall survival benefit in randomized trials; second-line chemotherapy with lomustine (CCNU), temozolomide rechallenge in MGMT-methylated tumors, or carboplatin combinations; and re-irradiation with stereotactic radiosurgery or hypofractionated radiotherapy for discrete, small-volume recurrences.

Most importantly, clinical trial enrollment is strongly recommended at the time of GBM recurrence. The limited proven benefit of available standard second-line therapies, combined with the rapidly expanding clinical trial landscape — including CAR-T cell programs, oncolytic viruses, neoantigen vaccines, and targeted agents — makes trial participation the most important option for recurrent GBM patients who maintain adequate performance status.

No — and this distinction is important. IDH-mutant Grade 4 astrocytoma was previously called 'secondary glioblastoma' and was grouped with IDH-wildtype GBM under the glioblastoma label. The 2021 WHO CNS Tumor Classification separated these into distinct entities based on their fundamentally different biology and prognosis.

IDH-mutant Grade 4 astrocytoma typically occurs in younger patients (often under 45), has a significantly more favorable prognosis than IDH-wildtype GBM — with median survival often measured in several years rather than months — and has a specific therapeutic target in the mutant IDH protein itself. IDH inhibitors (vorasidenib, ivosidenib, olutasidenib) have demonstrated activity in IDH-mutant gliomas and are an important class of clinical trials specifically relevant for IDH-mutant Grade 4 astrocytoma. If you have been told you have 'glioblastoma' but your IDH status shows a mutation, discussing with a specialist neuro-oncologist whether your diagnosis should be reclassified as IDH-mutant Grade 4 astrocytoma — and what trial options this opens — is strongly recommended.

Yes — glioblastoma is one of the most actively researched cancers globally, and clinical trial participation is particularly important given the limited efficacy of current standard second-line therapies at recurrence. Active research areas include: immunotherapy combinations overcoming GBM's immunosuppressive microenvironment; personalized neoantigen vaccines combined with pembrolizumab; EGFRvIII and GD2-directed CAR-T cell therapies (with intracranial delivery approaches); oncolytic viruses including PVSRIPO and DNX-2401; IDH inhibitors for IDH-mutant Grade 4 astrocytoma; and CDK4/6 inhibitors for CDK4-amplified tumors.

In China, multiple specialist neuro-oncology centers in Beijing, Shanghai, and Guangzhou are running active GBM trials — including EGFRvIII-directed CAR-T programs, GD2-targeting CAR-T approaches, and novel immunotherapy combination studies — that may not be available in India or other countries. CancerFax can review your molecular profile and treatment history against currently open trial criteria and support coordination with enrolling centers, including in China. Trial eligibility assessment at the time of first recurrence — before performance status declines — is particularly time-sensitive.

Yes. CancerFax supports glioblastoma patients and families through the full treatment navigation process. We begin with a detailed review of your MRI reports, surgical pathology, MGMT methylation result, IDH status, EGFR amplification status, TERT mutation, and comprehensive NGS findings — to confirm the molecular classification (IDH-wildtype GBM vs. IDH-mutant Grade 4 astrocytoma), assess the completeness of molecular workup, and identify which treatment options are most relevant.

Based on this review, we identify which approaches apply — from neurosurgical second opinions for resectability assessment and TTFields access coordination for newly diagnosed GBM, to bevacizumab, lomustine, or temozolomide rechallenge for recurrent disease, to IDH inhibitor trials for IDH-mutant Grade 4 astrocytoma, CAR-T programs (EGFRvIII or GD2-directed) and oncolytic virus trials at specialist neuro-oncology centers in China, the US, and Europe. We coordinate second opinion consultations with specialist neuro-oncologists and facilitate international treatment navigation for patients seeking trial access or advanced therapies not locally available. Send your medical reports to get started.