Researchers from the Abramson Cancer Center of the University of Pennsylvania have found that liquid biopsy can help to predict the prognosis of glioblastoma(GBM), the most aggressive and common brain cancer in adults.

The study indicated that patients with a higher concentration of cfDNA have shorter progression-free survival than those with less cfDNA. Furthermore, cfDNA increases in patients either at the time of or just before their disease progresses.

Liquid biopsy was compared with the genetic sequencing of solid tissue biopsies in GBM cases.

Both biopsies detected the genetic mutations in over half of the patients and none of the mutations overlapped, indicating that the liquid biopsy may provide complementary information about the genetic constitution of each tumour.

An estimated 11,000 cases of GBM are diagnosed every year, with a five-year survival rate between 5 and 10%.

Penn’s Perelman School of Medicine assistant professor Stephen J Bagley said: “If our findings are validated by further studies, it would mean that these patients may be able to get a simple blood test that would give us a more accurate assessment than imaging of whether their disease has progressed or not, as well as more data on the mutations in their tumours.”

The study included 42 patients newly diagnosed with GBM who had undergone blood tests at diagnosis, before surgery and at regular intervals throughout their treatment.

The 28 patients with a lower concentration of cfDNA at pre-surgery had approximately 50% chance of progression-free survival versus 14 patients with higher concentrations.

Researchers also intend to carry out tumour DNA sequencing on multiple samples of the resected tumours of each patient to gain an understanding of the full molecular profile in the future.