Glioblastoma (GBM) is the most aggressive and common type of brain cancer. Classified as a Grade 4 brain tumor, GBM cells rapidly grow and infiltrate surrounding brain tissue, making treatment challenging.
Understanding Prognosis
Prognosis for glioblastoma refers to the expected course of the disease. For adults diagnosed with GBM, average survival ranges from 12 to 18 months, with a median often cited around 14.6 to 15 months. Individual experiences can vary considerably.
A small percentage of patients survive longer, with approximately 25% living beyond one year and 5% to 6.8% surviving five years or more. These statistics provide a general outlook, not individual predictions. Research continuously seeks to improve survival rates.
Key Factors Influencing Survival
Several factors influence glioblastoma survival, including patient characteristics and tumor biology. Younger individuals, particularly those under 55, generally have a more favorable prognosis.
A patient’s overall health and functional status, assessed by the Karnofsky Performance Scale (KPS), also plays a role. Higher KPS scores are associated with longer survival. Tumor location can also impact treatment feasibility and survival.
Tumor characteristics provide additional prognostic insights. The extent of surgical removal (EOR) is a significant determinant. Achieving a maximal safe resection, especially a gross total resection (GTR) where over 99% of the visible tumor is removed, is linked to notably longer survival times. Patients undergoing GTR may have a median survival of 20-25 months.
Molecular markers offer prognostic information. The isocitrate dehydrogenase (IDH) mutation status is one marker; glioblastomas with IDH mutations (IDH1 or IDH2) are associated with longer median survival, potentially around 31 months, compared to IDH-wildtype tumors which are more aggressive. Another marker is the methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) gene promoter. Tumors with a methylated MGMT promoter respond better to certain chemotherapies and exhibit longer survival, often 21.7 months compared to 12.7 months for unmethylated MGMT.
Impact of Treatment Approaches
Standard glioblastoma treatments aim to extend survival. Surgical resection is typically the initial step, focusing on removing as much of the tumor as safely possible. Maximal safe resection is foundational, as greater tumor removal is consistently associated with improved outcomes. Complete removal is challenging due to GBM’s infiltrative nature.
Following surgery, radiation therapy is standard. It uses high-energy beams to destroy remaining cancer cells, reducing recurrence. Radiation is often administered with chemotherapy, forming a combined approach.
Temozolomide (TMZ) is the primary chemotherapy drug for glioblastoma and the only FDA-approved therapy demonstrating a survival benefit. Given concurrently with radiation and then as adjuvant treatment, TMZ extends median survival for newly diagnosed patients from 12.1 months to 14.6 months. This improvement is particularly pronounced in tumors with MGMT promoter methylation. Tumor Treating Fields (TTFields), a non-invasive therapy using alternating electrical fields to disrupt cancer cell division, is also approved. Combined with temozolomide for newly diagnosed GBM, TTFields can extend median survival from 15.6 months to 20.5 months.
Emerging Therapies and Clinical Trials
Research explores new avenues for improving glioblastoma prognosis, with several promising therapies under investigation. Targeted therapies, focusing on specific molecular pathways in cancer growth, represent one area of active development. These treatments aim to precisely attack cancer cells.
Immunotherapy is another evolving field, harnessing the body’s immune system to fight the tumor. Approaches include immune checkpoint blockade, CAR T-cell therapy, oncolytic virotherapy (using viruses to target cancer cells), and vaccine therapies. Clinical trials evaluate these novel agents, often in combination, for effectiveness and safety.
Clinical trials test new drugs and treatment strategies, from novel chemotherapy to innovative uses of existing technologies like TTFields with immunotherapy. These studies are crucial for identifying breakthroughs that could alter the outlook for glioblastoma patients. Progress in understanding GBM biology fuels advanced therapies, offering hope for improved survival and quality of life.