Tumor Treating Fields (TTFields)/Electrical Fields

Tumor treating fields, a type of cancer therapy, use low-energy electrical fields to disrupt cancer cells’ ability to grow and divide. TTFields may also be called alternating electric fields.

How is TTFields therapy used to treat tumors?

TTFields therapy is delivered through electrodes placed on your skin near the tumor. These electrodes are connected to a portable device you can carry in a backpack or messenger bag. The device sends mild electrical currents that target cancer cells while sparing most nearby healthy cells. The TTFields device usually needs to be worn for at least 18 hours each day.  People can continue most of their daily activities while wearing it. Your cancer care team will teach you how to use the device and how to place the electrodes on your body.

TTFields can be used alone or with other treatments, such as chemo or immunotherapy. TTFields therapy tends to have fewer side effects than chemo or radiation, so it may be used if other treatments have already been tried.

Two tumor treating fields devices are FDA-approved to treat cancer:

• Optune Gio is approved for new or recurrent glioblastoma (GBM)
• Optune Lua is approved for pleural mesothelioma that can’t be removed with surgery and metastatic non-small cell lung cancer  that’s grown during or after treatment with chemo.

Research studies are also looking at using TTFields for other types of cancers, such as pancreatic cancer.

Do TTFields devices use radiation?

TTFields devices do use radiation, but it’s different from traditional radiation therapy. The electrical fields created in TTFields are a type of non-ionizing radiation. Other types of non-ionizing radiation include radio waves, microwaves, and visible and infrared light.

Non-ionizing radiation doesn’t have as much energy as ionizing radiation. Traditional radiation therapy uses high-energy ionizing radiation to kill cancer cells. Ionizing radiation can hurt healthy cells nearby and possibly cause side effects.

What are the side effects of TTFields therapy?

Side effects of treatment with TTFields devices are usually limited to the electrode sites. The electrodes are applied to the skin with adhesive patches. Side effects can include:

• Skin irritation
• Allergic reactions
• Local warmth and tingling sensations
• Muscle twitching
• Infections
• Breakdown of the skin (ulcers)

Other side effects are also possible. For example, TTFields electrodes worn on the head can cause:

• Headaches
• Sleep problems
• Mood changes
• Increased risk of seizures

Some people might not be good candidates for treatment with a TTFields device, because of other health issues they have. Talk to your doctor to learn if this type of treatment might be right for you.

For more information on tumor treating fields

Learn more about how tumor treating fields are used to treat glioblastoma, mesothelioma, and non-small cell lung cancer.