Tumor Treating Fields (TTFields) Treatment

Tumor Treating Fields (TTFields) are a new type of cancer treatment that use low intensity electrical currents to prevent tumors from growing or spreading. TTFields were approved for the treatment of pleural mesothelioma cancer in 2019, after proving efficacy in clinical trials. The therapy results in fewer side effects and has increased overall survival in patients involved in the STELLAR study.

elderly woman talks to her doctor as the doctors holds a tablet device. both wear face masks.

Tumor Treating Fields (TTFields) for Mesothelioma Treatment

Tumor Treating Fields (commonly called TTFields) is a new mesothelioma cancer treatment that uses electrical currents to fight solid cancers. The therapy involves placing pads on the chest that are connected to a small, portable medical device. The “transducer arrays” pass a low intensity, alternating electrical current through the skin that disrupts tumor cell growth.

TTFields treatment–prescribed in combination with chemotherapy–increased median overall survival by 18.2 months in a study of malignant pleural mesothelioma patients.

Previously, TTFields were used to treat glioblastoma multiforme. Currently, glioblastomas are the most common and most aggressive type of brain cancer. In a study of 695 patients with glioblastomas, TTFields with maintenance chemotherapy (temozolomide) increased average lifetime survival by 1.8 years. Moreover, patients who survived the first two years after diagnosis had a 20.7% chance to pass 10 years of survival.

Novocure is the medical manufacturer responsible for creating the TTFields treatment. Formerly, the treatment was known as the NovoTTF-100L System. Today, Optune™ is approved to treat certain brain cancers. Optune Lua™ is the brand name of this specific mesothelioma cancer therapy.

From 2015 to 2017, researchers studied the effects of the treatment on 80 patients with inoperable malignant pleural mesothelioma. Patients received a combination of intravenous chemotherapy cycles using pemetrexed and platinum (carboplatin or cisplatin).

Study results:

  • Median overall survival was 18.2 months (up from 12.1 months)
  • Progression-free survival increased to 7.6 months (up from 5.7 months)
  • 2% of patients experienced benefits from treatment
  • No treatment-related deaths or serious unfavorable effects occurred

Side Effects

In 2019, the Food and Drug Administration (FDA) approved TTFields (with maintenance cycles of chemo) for the treatment of unresectable malignant pleural mesotheliomas. Unresectable tumors cannot be removed via surgery–usually because tumors have spread too far or are hard for surgeons to reach.

In the STELLAR study, 66% of patients were diagnosed with the epithelioid mesothelioma cell type.

The FDA approves new treatments like TTFields because they proved to be as or more effective than current therapies and medication. In the 80-patient trial, the low-intensity electrical fields used in treatment didn’t produce the severe side effects associated with other invasive or harsh cancer therapies.

Side effects of TTFields reported in the trial included:

  • Fatigue
  • Mild to moderate dermatitis (skin rash, itchiness, redness) from electrical pads
  • Other side effects caused by combination chemotherapy treatment

The transducer pads placed on the chest for TTFields treatment have a gel coating (like EKGs’ hydrogel) that causes an allergic reaction in some patients. The coating is a conductive hydrogel and must remain in contact with the body for most of the day throughout treatment. Those who are allergic to the hydrogel may not be candidates for TTFields cancer therapies.

The transducer arrays do not produce heat and, as a result, won’t cause burns when left on the skin for hours.

Less than 10% of trial participants using Novocure’s NovoTTF-100L device experienced side effects with chemotherapy like:

  • Abnormal physical weakness
  • Anemia
  • Chest pain
  • Constipation
  • Cough
  • Fatigue
  • Itchy skin
  • Medical device site reaction
  • Nausea

How Do TTFields Devices Treat Mesothelioma?

From the outside, TTFields treatment may look a little like putting TENS units on the body for nerve pain. The device is wearable and portable, meaning patients take it with them when they leave the doctor’s office. Tumor treating fields, however, work by disrupting cancer cell division.

Novocure’s tumor treating fields work via several mechanisms of action. TTFields Optune therapy disrupts cancer DNA repair, tumor survival, and other cancer cell biological processes.

Four electrical pads, called transducer arrays, are placed on the skin in the location of tumors. For pleural mesothelioma patients, the chest and back typically make good locations for pad placement.

For the best results, the device should be worn for at least 18 hours every day (even during sleep). If the device is worn at least 75% of each day, patients can wear it whenever they choose and can take breaks when needed.

Inside the body, the medical device creates TTFields via low intensity, alternating electric fields. The fields target and slow certain proteins in cancer cells that would otherwise allow cells to divide out of control. TTFields may slow, stop, or kill mesothelioma cells.

Patients with implanted electrical devices (like pacemakers and automatic defibrillators) should not use TTFields devices. The device’s electrical output of 150 kHz could cause implanted electrical devices to stop working properly.

Simultaneous chemotherapy with TTFields administers the following medications every 21 days for up to 6 cycles:

  • Intravenous pemetrexed
  • Intravenous cisplatin or carboplatin

How Do I Get TTFields for Cancer Treatment?

The FDA approved Optune Lua or TTFields treatment as a first-line treatment for “patients with unresectable, locally advanced or metastatic malignant pleural mesothelioma.” Your doctor can prescribe TTFields for the treatment of your cancer if you meet FDA requirements. Ask your doctor if you qualify for treatment.

To administer the Optune Lua treatment, doctors must be certified by Novocure. Over 1,300 treatment centers in the U.S. are Novocure-certified.

In the STELLAR study, patients had not undergone chemotherapy or radiation and wouldn’t benefit from surgery. Yet, TTFields with maintenance chemotherapy improved overall survival compared to patients with chemotherapy alone. The frequency of the fields has been shown to harm cancer cells but does not affect healthy cells.

Cost of TTFields Therapy

The NovoTTF-100L System was the first FDA-approved treatment for malignant pleural mesothelioma in 15 years. The goal of tumor treating fields was to extend lifetime survival in those with the most aggressive cancers.

Known as Optune Lua today, the International Association for the Study of Lung Cancer reported the cost of TTFields treatment was about $21,000 per month.

Patients who have been prescribed Optune Lua by their doctor can work with Novocure for insurance plan support to minimize costs. The medical company will also provide technical support and device training to you and your caregivers.

Veterans may be able to use VA health care to access treatment. Mesothelioma is generally considered a service-connected illness and a covered health benefit.