What is GBM?


About glioblastoma

Glioblastoma, or GBM, is a type of primary brain cancer. This means that GBM tumors begin in the brain, rather than starting in another part of the body and traveling to the brain. GBM is the most common type of primary brain cancer in adults.

Dennis, an Optune Gio user and Patient Ambassador

Who gets GBM?

You or your loved one’s diagnosis may have been the first time you heard about GBM. Because of this, it may seem like GBM is rare compared with other types of cancer. But you are not alone.

Behind the Mystery: Glioblastoma

Learn more about glioblastoma, or GBM, a rare tumor found in the brain that can be difficult to treat.

What part of the brain does GBM affect?

Most people get GBM tumors in their cerebral hemispheres. These are the left and right halves of the brain that control reading, thinking, speech, muscle movement, and emotions. Rarely, GBM can also appear in the brain stem or spinal cord.

What symptoms does GBM cause?

GBM rarely spreads to other areas of the body. But GBM tumors can grow quickly in the brain. Because of this, you may have noticed symptoms that appear suddenly, as if out of nowhere.

As a GBM tumor grows, it can put pressure on the brain. This can cause:

Nausea and vomiting

Depending on the location of the tumor, GBM can also interfere with how the brain controls other parts of the body. This can lead to:

Weakness on one side of the body
Difficulty with
memory or speech
Changes in vision

The difference between newly diagnosed GBM and recurrent GBM

Newly diagnosed GBM

When a GBM tumor is first confirmed by your doctor, it’s called newly diagnosed GBM. This means that the tumor has not been treated previously.

Recurrent GBM

Recurrent GBM is when GBM has come back after a period of time and a GBM tumor is visible on your MRI. Prior treatments may have removed or destroyed most GBM tumor cells. But some cancerous cells may remain and continue to grow. That’s because of the location of the tumor and the "finger-like tentacles" of a GBM tumor that may spread across the brain, making it difficult for treatment to reach all GBM cells.

How GBM is treated
Learn about options
Get to know Optune Gio
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Talk to your doctor
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Important Safety Information

What is Optune Gio® approved to treat?

Optune Gio is a wearable, portable, FDA-approved device indicated to treat a type of brain cancer called glioblastoma multiforme (GBM) in adult patients 22 years of age or older.

Newly diagnosed GBM

If you have newly diagnosed GBM, Optune Gio is used together with a chemotherapy called temozolomide (TMZ) if:

  • Your cancer is confirmed by your healthcare professional AND
  • You have had surgery to remove as much of the tumor as possible

Recurrent GBM

If your tumor has come back, Optune Gio can be used alone as an alternative to standard medical therapy if:

  • You have tried surgery and radiation and they did not work or are no longer working AND
  • You have tried chemotherapy and your GBM has been confirmed by your healthcare professional

Who should not use Optune Gio?

Optune Gio is not for everyone. Talk to your doctor if you have:

  • An implanted medical device (programmable shunt), skull defect (missing bone with no replacement), or bullet fragment. Optune Gio has not been tested in people with implanted electronic devices, which may cause the devices not to work properly, and Optune Gio has not been tested in people with skull defects or bullet fragments, which may cause Optune Gio not to work properly 
  • A known sensitivity to conductive hydrogels (the gel on the arrays placed on the scalp like the ones used on EKGs). When Optune Gio comes into contact with the skin, it may cause more redness and itching or may rarely cause a life-threatening allergic reaction

Do not use Optune Gio if you are pregnant or are planning to become pregnant. It is not known if Optune Gio is safe or effective during pregnancy.

What should I know before using Optune Gio?

Optune Gio should only be used after receiving training from qualified personnel, such as your doctor, a nurse, or other medical staff who have completed a training course given by Novocure®, the maker of Optune Gio.

  • Do not use any parts that did not come with the Optune Gio Treatment Kit sent to you by Novocure or given to you by your doctor
  • Do not get the device or transducer arrays wet
  • If you have an underlying serious skin condition on the scalp, discuss with your doctor whether this may prevent or temporarily interfere with Optune Gio treatment

What are the possible side effects of Optune Gio?

Most common side effects of Optune Gio when used together with chemotherapy (temozolomide, or TMZ) were low blood platelet count, nausea, constipation, vomiting, tiredness, scalp irritation from the device, headache, seizure, and depression. The most common side effects when using Optune Gio alone were scalp irritation (redness and itchiness) and headache. Other side effects were malaise, muscle twitching, fall and skin ulcers. Talk to your doctor if you have any of these side effects or questions.


Please click here for the Optune Gio Instructions For Use (IFU) for complete information regarding the device’s indications, contraindications, warnings, and precautions.

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This website is intended for people seeking information on Optune Gio.

On this site, videos and images identified as Optune Gio users, caregivers, or healthcare professionals depict actual patients, caregivers, and healthcare professionals.

Patient images reflect the health status of the patients at the time each photo or video was taken.


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US-OPG-00063 v2.0 March 2024