Skip to main content

ACS & ASCO are Stronger Together: Cancer.Net content is now available on


Tumor Treating Fields (TTF) Therapy for Adult Brain and Spinal Cord Tumors

Researchers have found that exposing some types of tumor cells to alternating electric fields. This treatment is also known as tumor treating fields, or TTF. This therapy can interfere with the cells’ ability to grow and spread. A wearable device known as Optune, is a TTF treatment that generates such electric fields. It is now an option to help treat some people with glioblastomas.  

For TTF therapy, the head is shaved, and 4 sets of electrodes are placed on the scalp. The electrodes are attached to a battery pack (kept in a backpack) and are worn for most of the day. They generate mild electric currents that are thought to affect tumor cells in the brain more than normal cells.

Optune can be used:

  • Along with chemotherapy in people with newly diagnosed glioblastoma after treatment with surgery and radiation therapy. It may help people live longer than if they just get chemotherapy alone.
  • Instead of chemotherapy in people whose glioblastoma has come back after initial treatment. It hasn’t been shown to help people live longer than chemotherapy in this situation, but it tends to have much milder side effects.

Possible side effects

Side effects of the device used for TTF tend to be minor, and can include skin irritation at the electrode sites, trouble sleeping, mood changes, and a slightly increased risk of headaches and seizures.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Dorsey JF, Salinas RD, Dang M, et al. Chapter 63: Cancer of the central nervous system. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Central Nervous System Cancers. V.3.2019. Accessed at on February 17, 2020.

Stupp R, Taillibert S, Kanner A, et al. Effect of tumor-treating fields plus maintenance temozolomide vs maintenance temozolomide alone on survival in patients with glioblastoma: A randomized clinical trial. JAMA. 2017;318:2306-2316.

Stupp R, Wong ET, Kanner AA, et al. NovoTTF-100A versus physician's choice chemotherapy in recurrent glioblastoma: A randomised phase III trial of a novel treatment modality. Eur J Cancer. 2012;48(14):2192-202.

Last Revised: September 6, 2023

American Cancer Society Emails

Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.