Tumor Treating Fields (Optune): What, How, Who, Why?

“Tumor Treating Fields (Optune) should be considered a standard of care for all eligible patients who are being treated with chemo-radiation for glioblastoma,” says Dr. James Taylor, radiation oncologist with North Georgia Physicians Group.

The first step in the treatment of GBM is maximally safe resection, where the neurosurgeon removes as much of the suspected tumor as possible without damaging important structures in the brain that would lead to significant neurologic deficits.

Because GBM is often very difficult to remove completely and because of the way the tumor grows, there is typically small amounts of residual disease that requires treatment following surgery. The treatment following surgery includes radiation to the surgical area and areas concerning for residual disease as well as an oral chemotherapy which is taken at the same time.

The radiation and chemotherapy are typically delivered for six weeks. Sometimes the radiation course can be shortened if your doctors do not think you would be able to tolerate the six week treatment course. The chemotherapy at this time is a low dose regimen that is given every day for the duration of radiation.

Approximately one month following chemotherapy and radiation, you begin your treatment with chemotherapy and tumor treating fields (Optune). The chemotherapy remains the same, but the dose is increased and you take the medication for five days followed by a three-week break. At the same time, you start using the tumor treating fields.

The tumor treating fields are worn every day for a majority of the day.

Tumor Treating Fields (Optune): What to Expect

The Optune device uses adhesive pads with electrodes that are applied directly to the skin. These are called transducer arrays and typically four of them are applied to the scalp. In order to be applied you need to shave your head prior to the using Optune. The Optune pads are worn continuously throughout the day for as long as possible, with minimal interruptions or breaks. For Optune to be maximally effective, studies have shown the pads need to be worn and activated for at least 18 hours each day, seven days a week.

The Optune device can be used for up to 24 months or until the disease progresses twice.

Optune: What’s the Data Look Like?

Initial studies were done in the lab on cancer cells demonstrating that using alternating electric fields led to improper division and slowed growth of cancer cells. Following promising data performed in the labs, small clinical trials were performed demonstrating that using Optune was effective and safe in patients with GBM.

“The reason Treating Tumor Fields is considered standard of care is because we have good evidence that they improve survival in patients with glioblastoma,” Dr. Taylor shared with SurvivorNet.

Eventually, a large prospective randomized clinical trial demonstrated that adding Optune to the treatment for GBM improved survival and slowed progression of disease. Due to the results of this study, addition of Optune to chemotherapy for patients 22 years and older became standard-of-care for the treatment of GBMs following surgery and chemoradiation.

What to Expect Day-to-Day

The Optune device consists of four adhesive pads applied to the scalp, connection cables, the electric field generator, portable batteries and charger, and a messenger bag to carry the device. The Optune device is relatively small and weighs about 2.7 pounds. Additionally, because it portable you can wear the device continuously as you go about your normal daily activities. Each Optune kit comes with four batteries which last for 2-3 hours at a time. There is also a wall power supply that allows you to plug in the device while you sleep or are changing batteries.

The adhesive pads are applied directly to the skin requiring patients to shave their heads. Before applying the pads, the scalp should be washed and dried. After placing the adhesive pads they can be worn for up to four days at a time and must be changed at least twice per week.

Patients can change the pads more frequently if they are sweating excessively, their hair grows too quickly, or they’re experiencing significant discomfort or itching.

Side Effects

Overall Optune is a well-tolerated treatment with mild side effects. The common side effects in the treatment of GBM are a result of the chemotherapy used, called temozolomide. Side effects from temozolomide can include but are not limited to:

• Low blood counts
• Nausea, vomiting
• Constipation
• Fatigue

The use of Optune does not increase the rate of side effects from chemotherapy. In regards to Optune specifically, it is common to experience mild to moderate skin irritation on the scalp when using the device, including itching and rash. It is extremely uncommon to experience a severe skin reaction.

Dr. Taylor tells us, “Another common side effect is skin irritation on the scalp where the transducer arrays are placed. If you develop side effects, there are many ways to mitigate these so communication with your treatment team is paramount.”

The Future of Tumor Treating Fields

Optune is currently indicated for use in patients that have already received surgery and chemoradiation for GBM. Again it can be used for up to two years following initiation of Optune treatment or until the time of a second recurrence of progression of the disease.

We know that Optune is effective when used after surgery and radiation, but can it be used during radiation as well? An ongoing clinical trial, TRIDENT, is trying to answer this question. TRIDENT is a randomized, prospective trial that is comparing patients that already received surgery. One group of patients received standard-of-care with chemoradiation followed by Optune and chemotherapy, while the second group of patients received Optune together with chemoradiation then followed by Optune and chemotherapy.

The goal of this trial is to see if the survival for GBM can be improved even further with earlier use of Optune during radiation. The trial has finished enrollment, and we are eagerly awaiting the results.

The use of Tumor Treating Fields (Optune) is now expanding outside the use of GBMs and has shown promising results in the treatment of lung cancer. This shows that the mechanism behind Optune works and that many other cancer patients may benefit in a similar way. If you have a Glioblastoma ask your treating team about Optune to see if it is right for you.

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