Tumor treating fields is the first new treatment approved by the U.S. Food and Drug Administration for mesothelioma in nearly fifteen years.[1] It uses electrical fields to target and destroy cancer cells. It is approved for use in combination with chemotherapy.
About Tumor Treating Fields
Tumor treating fields is a cancer treatment developed, made, and sold by Novocure. The company has been working on TTFields since 2000 and saw its first FDA approval in 2011 for the treatment of glioblastoma, a type of brain cancer.[2]
What Is Tumor Treating Fields?
TTFields is a noninvasive treatment that destroys cancer cells by using alternating electric fields of low intensity and intermediate frequency. The fields are delivered through pads that stick to the skin. There is no surgery involved, but oncologists use it together with chemotherapy.
How Does TTFields Work?
Researchers think TTFields works by disrupting cell division. Cancer cells grow, divide, and multiply rapidly. Healthy cells have controls in place to limit this, but malignant cells divide at a runaway pace.
Electric fields disrupt the formation of the spindle in a dividing cell. In other words, they interfere with structures within the cell that must separate for it to divide and create new cells.
What Does TTFields Treat?
Some of the first studies of TTFields included patients with glioblastoma, a difficult type of brain cancer. Results indicated the treatment could extend survival time and improve patient quality of life.[3]
Since then, the FDA has approved tumor treating fields for the treatment of both glioblastoma and mesothelioma.
TTFields – One of the Latest Treatments for Mesothelioma
Once the FDA approved TTFields for use in patients with glioblastoma, researchers began testing the system in patients with mesothelioma.
The positive results of the phase II STELLAR clinical trial led to FDA approval of TTFields used along with chemotherapy using pemetrexed and cisplatin or carboplatin. It was approved in 2019 as a Humanitarian Use Device for advanced, unresectable pleural mesothelioma.[1]
Is TTFields Effective for Treating Mesothelioma?
In the STELLAR trial, patients were given the therapy at twelve different European locations. Eight patients with pleural mesothelioma received TTFields therapy and chemotherapy every three weeks for as many as six cycles.[4]
Results showed promise for treating mesothelioma patients:[5]
- At follow-up appointments, researchers found that the mean survival time was 18.2 months.
- At one year, 62.6% of the patients were still living.
- At two years, 41.9% still lived.
- Only 3% of treated patients saw disease progression; 57% saw stability in their cancer; 40% exhibited a partial response.
- In addition to extended survival times, the researchers found no increased toxicity in the patients and only mild adverse effects related to the TTFields.
The Most Recent TTFields and Mesothelioma Research
The original clinical trials showed great promise and led to the approval of TTFields for some patients with pleural mesothelioma. Because of this, research is ongoing.
Much of the current research is in cell lines. The researchers hope to understand how the treatment works, which will help them create better and more effective treatments for patients.
Is TTFields a Treatment Option for Mesothelioma?
Tumor treating fields is approved for mesothelioma, but it is not a standard treatment. The FDA’s approval is for treatment within a very specific framework:[1]
- Patients with pleural mesothelioma, who are not candidates for surgery
- Patients with either locally advanced or metastatic pleural mesothelioma
- A first-line treatment in combination with standard chemotherapy, which is pemetrexed and a platinum-based drug
These guidelines do not mean oncologists cannot use TTFields for other patients. However, it remains an uncommon therapy for mesothelioma.
What Are the Benefits of TTFields Treatment?
While TTFields is still considered experimental, there are several proven benefits:
- Studies show that TTFields can extend a patient’s survival time compared to only receiving chemotherapy.
- TTFields devices are noninvasive and portable, so patients can receive treatment at home and while doing other activities.
- Side effects of TTFields are minimal.
- TTFields treatment may be more cost-effective than other treatments, especially if patients must travel to receive them. Some patients may qualify for financial assistance from the manufacturer.
How Can Mesothelioma Patients Access TTFields?
This is still a limited treatment for mesothelioma, but you might be able to access it. Talk to your medical team about your options. They might not offer it, but they could recommend a treatment center that does.
You can also talk to your team about clinical trials. A trial to test the use of TTFields in pleural mesothelioma patients as part of routine care has not yet begun recruiting.[6] When it opens, your medical team can help determine if you are eligible to participate.
What to Expect When Using TTFields
The medical device used for this therapy was previously known as the NovoTTF-100L. It is now branded as Optune Lua. The device is small and portable and does not need to be used in a hospital or physician’s office. In fact, it is designed to be easily carried so that treatment can continue on the go.
It includes four pads, two that attach to the back and two that stick to the chest. The patient must first shave the skin. They also need to change the pads every few days.
Patients wear the pads and keep the device with them for up to twenty hours a day during the course of treatment. The device delivers the electric fields through the pads. It needs to be charged regularly.
What Are the Side Effects of Tumor Treating Fields?
The TTFields therapy itself does not cause many side effects. The treatment can only be used along with chemotherapy, so patients do usually experience side effects, but they are overwhelmingly caused by the chemotherapy:[4]
- Anemia, weakness, and fatigue
- Low white blood cell count, resulting in a weakened immune system
- Nausea
- Weight loss
- Constipation
The only reported adverse event triggered by the TTFields device was dermatitis at the site of the pad placement with symptoms including rash, itchiness, and irritation. The skin reaction was generally reported as mild to moderate.[5]
Who Should Not Use TTFields?
The candidates for TTFields with chemotherapy are patients with mesothelioma that cannot be treated surgically and that has spread. There are also several contraindications for safety reasons.
Patients with implanted electronic devices, like pacemakers, should not receive this kind of treatment. It has not been tested for safety with these devices.[7]
You should not use TTFields if you are to conductive hydrogels. This is the material placed between the device pad and the skin. It can cause a life-threatening allergic reaction in some people.
Pregnant women are also discouraged from using TTFields. It is not known how it could affect pregnancy or a developing fetus.[7]
How to Use TTFields Safely
Before using TTFields at home, you must be trained by a medical professional in proper use:[6]
- It is important to keep the device dry and away from water sources.
- Be careful around the cord, which can be a tripping hazard.
- If you have a skin condition where the pads will be placed, mention this to your doctor or nurse.
Tumor treating fields is an exciting new therapy and weapon in the battle against pleural mesothelioma. Although it still requires chemotherapy, the TTFields treatment does not increase chemotherapy toxicity or cause any serious side effects.
It does extend life expectancy for most patients. Talk to your medical team or oncologist to determine if you may be a good candidate for this new therapy.
