Blood Test for Aggressive Brain Tumors: Early Glioblastoma Detection Could Cut Surgical Risk

Why Is Early Detection of Glioblastoma So Difficult?

Glioblastoma is the most common and most aggressive primary malignant brain tumor in adults. Classified as a grade 4 glioma by the World Health Organization, it typically infiltrates surrounding brain tissue and is rarely curable with surgery alone. Early symptoms such as headaches, subtle cognitive changes or seizures overlap with many benign conditions, so diagnosis is often delayed until the tumor has grown large enough to produce clear neurological deficits or be visible on imaging.

Definitive diagnosis currently relies on MRI followed by neurosurgical biopsy or resection, both of which carry risk of bleeding, infection and neurological injury. A reliable blood-based test would allow earlier suspicion of the tumor, potentially before it has reached a size where extensive surgery is required, and could also help monitor recurrence without repeated biopsies.

How Does the New Blood Test Work?

Liquid biopsy approaches, including those developed in the University of Sussex-led collaboration, look for cancer-specific signatures in peripheral blood, such as fragments of circulating tumor DNA, RNA and tumor-associated proteins released into the bloodstream. Because glioblastoma cells have distinctive molecular features, researchers can train analytical models to distinguish patients with the tumor from healthy individuals and from those with less aggressive lesions.

If confirmed in larger, multicenter studies, such a test could be used alongside MRI to prioritize which patients need urgent neurosurgical assessment and which can be monitored, reducing unnecessary surgery. It could also support ongoing surveillance after treatment, detecting molecular recurrence earlier than imaging and enabling faster decisions about additional therapy.

What Could This Mean for Patients and Care Pathways?

For patients, an accurate blood test would mean fewer diagnostic biopsies, faster referral to specialist neuro-oncology centers, and potentially earlier initiation of surgery, radiotherapy and temozolomide-based chemotherapy, which remain standard of care. Earlier treatment may not cure glioblastoma, but it can influence the extent of safe surgical resection and quality of life in the months that follow diagnosis.

Health systems could also benefit if the test reduces emergency presentations and shortens diagnostic pathways. However, experts caution that blood tests for brain tumors must undergo rigorous prospective validation before routine use, including evaluation of false-positive rates, cost-effectiveness, and how the test performs in diverse populations and health care settings.