What is glioblastoma and why is it so hard to treat?

Glioblastoma is one of the most aggressive forms of brain cancer. (Supplied by Cure Brain Cancer Foundation)

The death of former Australian of the Year Richard Scolyer overnight came after a multi-year fight with one of the most difficult to treat cancers.

Glioblastoma is known as the most aggressive form of brain cancer.

And while there have been vast improvements in our ability to treat other cancers, such as melanoma, survival rates for this fast-growing brain cancer remain stubbornly low despite years of research and funding.

So what is it about glioblastoma that makes it so hard to treat?

Glioblastoma is part of the glioma family of tumours, and is a serious and aggressive stage 4 brain cancer.

Professor Lenka Munoz, a professor of molecular cancer pharmacology, says these tumours develop from glial cells, which support neurons in the brain.

"It accumulates several mutations, then becomes malignant and starts proliferating without control.

"These cells keep on dividing, and eventually form a small tumour," she says.

The tumours are difficult to treat and largely resistant to chemotherapy.

Average survival rates are between 12–18 months, with just five per cent of patients surviving longer than five years.

Nearly half of all primary malignant brain tumours are glioblastoma.

It's estimated that roughly 200,000 people die per year worldwide, including 1,000 Australians.

Professor Scolyer was diagnosed in June, 2023, after suffering a seizure while in Europe.

He acted as "patient zero" for a world-first immunotherapy treatment prior to surgery, which temporarily removed the tumours.

Professor Richard Scolyer after a complex surgery in March 2025, which unfortunately showed his brain cancer had returned. (Supplied: Instagram/@profrscolyer)

Other notable deaths from glioblastoma include fashion designer Yves Saint Laurent, Ted Kennedy, Joe Biden's son Beau, and author Sophie Kinsella who died in 2025.

Glioblastoma affects more males than females, and the median age of patients is 64.

It's currently unclear whether lifestyle factors or genetics play a part in risk factors.

There is no known cause of glioblastoma, Professor Munoz says.

"There is not one clear mutation that we could use as a diagnosis — we don't know why patients develop glioblastoma," she says.

Early detection can improve outcomes however glioblastoma remains one of the most difficult cancers to treat.

Current medical interventions include surgery to remove tumours followed by chemotherapy and radiation.

Unfortunately, glioblastoma commonly returns soon after treatmen