For patients diagnosed with the most aggressive kind of brain tumor, the average life expectancy is less than a year. University of Washington doctors are hoping to improve those odds. They're the first in the Northwest to use a new cap that helps control tumor growth.
Maciej Mrugala, M.D., Neurocologist at the University of Washington, talks about using an electrical field as a way to stop cancer cell growth and shrinkage of tumor.
What is glioblastoma?
Dr. Mrugala: Glioblastoma is one of the most deadly forms of human cancers. It exclusively originates in the brain and typically leads to a patient’s death within a year even with the best of treatments.
What happens with these patients?
Dr. Mrugala: These patients typically undergo several different treatment modalities. When the tumor is found the first treatment offered is surgery which allows us not only to remove the tumor but also to identify the pathological diagnosis. And once the glioblastoma is diagnosed the patient is offered either standard of care which includes radiotherapy and chemotherapy or if eligible can also be offered an experimental treatment in the setting of a clinical trial.
Glioblastomas are tumors with a bunch of tentacles, correct?
Dr. Mrugala: Correct. Glioblastoma doesn’t really have a capsule. It really grows invasively and as you mentioned has “tentacles.” The tumor infiltrates the healthy brain and that’s why it’s so difficult to remove it completely. And even with the best surgery there’s always a residual disease left behind.
Is TT Fields in a clinical trial right now?
Dr. Mrugala: Tumor treatment fields have already been approved by FDA to use for patients with recurring glioblastoma, never the less there are ongoing trials using this modality in patients with newly diagnosed glioblastoma in combination with chemotherapy.
So what is it exactly?
Dr. Mrugala: Tumor treating fields are really a very novel approach to treating cancer, not only glioblastoma. It’s a method that utilizes electrical field as a way to arrest cells in divisions leading to shrinkage of the tumor, thru cell apatosis, (cell death).
Electrical fields are used so much for stimulation why doesn’t it stimulate the cells to grow more?
Dr. Mrugala: Electrical fields have been known and used in medicine for quite a while now and their biological activity is heavily dependent on the frequency. And so let’s look at the very low frequency electrical field, something that’s less than one kilohertz. These electrical fields typically can have as you said stimulatory affects. Studies show that this type of field can stimulate bone growth and can also facilitate fracture healing. Then you have very high frequency fields in the range of megahertz and these types of fields are also used in medicine to treat cancer and, one of the examples, is radio frequency ablation. Very high frequency fields lead to tissue heating and by this mechanism lead to tissue damage. And then finally you have this intermediate frequency fields, typically between one hundred and three hundred kilohertz. These fields have been found to have inhibitory effects on dividing cells. These are the fields that were named tumor treating fields and these are the fields that are utilized in this device known as NovoTTF.
Is it dangerous for the patient at all?
Dr. Mrugala: As far as we know right now. It doesn’t have detrimental effects to the patient. The device has not been on the market for that long and I think that long term studies will show us if there are any long term effects. But at this point the device is considered pretty safe.
But this is no surgery, right?
Dr. Mrugala: Correct. This device is in a way very noninvasive, if you will. It is applied to the patients scalp externally. It does not require the patient to undergo surgical intervention and can be pretty much controlled by the patient, outside of the initial application that is done in the physician’s office.
Are there any bad side affects?
Dr. Mrugala: There are some side effects. They are predominately related to some local affects of the treatment field. The patients can sometimes feel sensation of heat being generated at the place where the arrays are located and also because of the fact that these treatment arrays have to be applied to the scalp continuously some patients develop skin irritation. For that reason, the arrays have to be repositioned every few days to let the skin recover.
And how long do they wear it?
Dr. Mrugala: The device is intended to be used continuously for the minimum of eighteen hours per day. So patients in theory can have about six hours a day when the device is not on. Because of the complexity of the application of the electrodes and time needed to do so, it is not recommended that they take the electrodes off. They stay on continuously until they are replaced. As I said before every three to seven days. The periods of replacement heavily depend on how fast the hair is growing. The scalp needs to be shaved before to maximize the conductivity and again when the hair starts growing.
Is this something you would use immediately after surgery for everyone or is this for the extreme cases that aren’t getting better?
Dr. Mrugala: At this point, we do not have efficacy data for this device to be used in newly diagnosed patients. So this would be reserved for patients who have failed initial treatment. These are patients who have already had surgery, who have already had radiation and chemotherapy and the tumor is coming back. This device is approved by FDA for this indication, for recurrent tumor.
So when you saw Reggie what was he like when you first met him?
Dr. Mrugala: Reggie was diagnosed several years ago. He was an extremely athletic guy. When the tumor was found of course it was devastating to find out. But he was extremely motivated to get better and we have really offered him a large menu of options including a clinical trial that we have developed here in Seattle using steps of transplantation for treatment of glioblastoma. Unfortunately the patient did not qualify for the study and underwent standard of care including radiation and chemotherapy and has initially responded very well to those treatments. However more recently the tumor progressed again and that’s why we have suggested consideration of a TTF device. The patient successfully started treatment about four weeks ago and has tolerated it very well and so far is doing really very well.
Could this get rid of the cancer or is this just buying time?
Dr. Mrugala: Well at this point I think it is probably just buying time. This was compared with chemotherapy and was found not to better. The studies are ongoing for newly diagnosed patients and we may see completely different results when this data becomes available.
So are your patients doing surgery and then chemo and then this?
Dr. Mrugala: The sequence will be most likely like this. Surgery will be the first approach, then radiation and chemotherapy and then when chemotherapy fails patients are being offered other options including TTF.
Is it something you’re recruiting patients for or is the trial underway? It is not a clinical trial.
Dr. Mrugala: It would be available to anyone who is eligible and wants to have it.
Are a lot of centers doing it right now?
Dr. Mrugala: No we are the only center in the Pacific Northwest that has the device. I think the next center that’s closest is California.