Vincent DiNapoli, MD, PhD, Neurosurgeon with Mayfield Brain and Spine, Director of the Brain Tumor Center at Mercy Jewish Hospital in Cincinnati, talks about a new way to treat brain cancers.
Can you tell me a little bit about the GammaTile? What is it and what is it designed to do?
Dr. DiNapoli: GammaTile was a novel therapy we adopted roughly about a year ago for certain types of recurrent tumors in the brain. A lot of patients had undergone initial surgical resection for removal of the tumor, then was followed by radiation treatment to the area and then chemotherapy. Once those patients have that brain tumor come back, which is common in a condition called glioblastoma (GBM), they’re in a situation where there aren’t a lot of other options to treat these tumors. So, this is an option where you can actually put radiation seeds in the cavity where the new tumor has come back at the time of surgery to deliver another dose of radiation to that area and try to kill residual tumors within the brain.
Is this primarily used for glioblastoma brain cancer or can it be used for any type?
Dr. DiNapoli: For our purposes, the use initially was for glioblastoma. Those were the patients that we felt it was best suited for – but the FDA has recently expanded the indications. Initially, the approval was for all recurrent brain tumors inside the head, like neoplasms. And then the recent expansion of that indication has been to use it initially when the patient presents the first time for surgery, not only when it recurs or comes back. It can be used for all newly diagnosed malignant and recurrent brain tumors.
Can you describe the procedure for when the tile is implanted?
Dr. DiNapoli: If it’s an initial use and this is the first time we’re doing the operation, we make the incision on the patient’s head and make a window in the bone to open up the bone and give us access to the inside. There’s a covering around the brain called the dura. We incise the dura and put that aside, then we remove the tumor as we normally would. When we’re done removing the tumor, we work with the radiation oncologist. The radiation oncologist brings the GammaTiles into the operating room, and we work with her to implant those tiles into the brain. It’s a collagen tile about the size of a postage stamp. You take that tile and put it against the brain and line the cavity where you’ve removed the tumor. Then, the radiation seeds in the GammaTile emit radiation into that cavity. So, basically the patient’s getting their treatment as soon as you put those radiation seeds in there and start closing surgery.
How many wafers do you have to use, or does it depend on the tumor?
Dr. DiNapoli: It honestly depends on the size of the tumor. Volumetrically, it just depends on the surface area that’s left behind when you remove the tumor. So, we’re lining the risk of the circumference of the cavity around where you removed the tumor with the tile.
You mentioned that it starts working immediately. How long does it release radiation, and what are the considerations for the patient? Are you radioactive?
Dr. DiNapoli: No, and that’s a good question because what we call brachytherapy, which means implanting radiation into the body, previously utilized I-125 seeds and the half-life for that was roughly 90 days. That’s a long time that the patient has to worry that this radioactive decay is happening and they’re emitting radiation. The nice thing with the GammaTile is it uses cesium instead of the iodine and the half-life for cesium is roughly 10 days. So, they’re getting the bulk of their radiation treatment within that first two weeks after surgery, which alleviates some concerns with being in proximity to loved ones and having that radioactive activity going on.
Can you explain what you mean by half-life?
Dr. DiNapoli: It’s a term we’re using in any kind of radiation. So, anything that’s emitting radiation, half-life refers to the amount of time it takes for half the amount of radiation that that source is going to deliver. Basically, it’s a measure of decay. Anything that’s emitting radiation decays over time. The radioactivity of that source goes down over time, and the shorter the half-life, the quicker that that radioactivity is going down.
Do the GammaTiles dissolve or do you have to remove them?
Dr. DiNapoli: They dissolve. It’s a re-absorbable matrix that they use. I think it roughly takes about three months for it to go away completely.
What’s the benefit to the patient to have this?
Dr. DiNapoli: I think there are multiple benefits for our GBM patients. It provides an option for these patients that are looking for something to hope for and a next step for their therapy. I think it’s very convenient for the patient. They don’t have to come back into the hospital for a second radiation treatment. Many of these patients would ultimately have to come back and have their tumor bed treated with radiation. So, it gives them that option of having a single event in the hospital. They come in, have their surgery, have the radiation implanted, go home and their treatment for that particular problem is completed. They don’t have to come back, which especially in times like COVID and all these concerns that we have, it’s nice that those vulnerable patients who are already sick don’t have to come in and out of the hospital sometimes up to 30 times to have radiation treatment.
Are you finding that it is as effective as standard radiation treatment?
Dr. DiNapoli: We’ve been doing brachytherapy in the brain for quite some time with I-125 seeds and that has been at least as effective. The recent therapy with GammaTile is pretty new. The FDA clearance is roughly two years old. So, the studies are ongoing. We’re comparing those to traditional radiation as well as other forms of brachytherapy to make sure that we’re providing the same results. We’re hoping it’s at least as good if not better. But, I haven’t seen any significant adverse consequences from it as far as side effects are concerned.
Which leads into my next question. What are the risks and side effects?
Dr. DiNapoli: The risk that we worry about anytime we deliver radiation into the brain, especially when the patient’s already been exposed to prior radiation, is the damage to the normal brain. Not just the tumor cells that are in the brain, but also the normal brain itself. That’s something called radiation necrosis. So, the brain cavity around where you place those seeds starts to die. It causes a lot of swelling in the brain, so we do worry about that. The initial studies with GammaTile showed a very, very low rate of that.
With brain surgery, I would imagine there is very little room for error. So, when you’re talking about necrosis, that can be pretty significant?
Dr. DiNapoli: Depends on where it is and how close it is to an eloquent or functional area of the brain. You can almost think of it like a brushfire. It begins in the cavity and starts kind of eating into the brain as the brain reacts to that process. We have good medications to treat it, but it is something that we worry about. Other concerns with these types of things would be if the wound is in close proximity to the radiation. You worry about wound healing issues or infections. You just have to be exceptionally fastidious with your technique to make sure that you’re closing things properly.
A couple of basic questions now about brain cancer tumors. How common are glioblastomas?
Dr. DiNapoli: Glioblastomas are relatively rare. I mean, as in the general population, it’s about one in a hundred thousand people have a glioblastoma. We, as brain surgeons, see them all the time and think that everybody has one. But, from a population standpoint, it’s a very rare disease.
How difficult has it been historically to treat?
Dr. DiNapoli: Exceptionally difficult. The problem with glioblastoma is that it’s a type of intrinsic brain tumor. We think about brain tumors in two categories, intrinsic brain tumors which start from the brain inside the brain itself, and metastasis or other type of extra axial tumors that come from somewhere else. Unlike meningiomas which grow outside the brain and push in on the brain, these are tumors that grow inside the brain itself. So, the problem with gliomas is they arise from the support cells of the brain called glial cells. Those glial cells are enmeshed in our brain along with all the neurons, and the neurons are the cells that make things happen in our brain. There are far more glial cells then there are neurons in our brain. When these glial cells become cancerous, they’re basically enmeshed in the brain with all the normal brain around it. We must remove that tumor from within the brain and those abnormal cells. The cells are centimeters, sometimes even four to six centimeters, away from that primary tumor, even sometimes on the opposite side of the brain. And we can’t go taking wide swaths of normal brain out just to try to catch these cells. So that’s the difficulty. Despite maximal surgical removal and radiation and chemotherapy, the vast majority of these patients suffer recurrence around the area where their primary tumor was, and it keeps coming back and eventually causes significant neurologic problems and ends up taking their life in most circumstances. We’ve been battling this disease for 35 years and we’ve made relatively small progress as far as overall survival. I think we’ve increased overall survival four to six months in 30 years.
Does having this technique help?
Dr. DiNapoli: That’s something we’ll have to figure out. I mean, the therapy we did with I-125 seeds was fairly successful in those patients. It’s not going to be the silver bullet for GBM, but it is an option for select patients that are good candidates. I think it is something that will extend their survival and provide them a good option.
And who are the good candidates for this?
Dr. DiNapoli: It’s any patient that’s had their primary resection and underwent radiation and chemotherapy. I think the best candidates are patients that have recurrence right along the margin of their primary resection cavity. It’s a fairly small area of recurrence, so that area can be resected, removed, and then the tile can be placed right up against that area where the tumor came back. So, we’re not only removing it, but we’re also treating those little cells we talked about that are in the brain still sitting there that we can’t see on the MRI. The radiation is penetrating the brain trying to kill those cells.
How can you be proactive with brain health?
Dr. DiNapoli: Brain health goes along with overall general health. I mean, all the things you think about with your general health contribute to your brain health. So, keeping a healthy cardiovascular system, maintaining a good exercise routine and a healthy diet. I think also the only additional thing with the brain is just adding to that mental activity, meaning maintaining active mental lifestyles, keeping active and mentally engaged.
But, in terms of preventing brain cancer, eating your veggies?
Dr. DiNapoli: That’s what’s so hard about GBM; it’s such a random thing and we don’t fully understand why it happens. It’s obviously some kind of combination of genetic predisposition with environmental exposure, but we don’t really know what those things are specifically. It’s a very devastating thing because it’s mostly a terminal diagnosis. And some of these patients are young, in their 40s and 50s.
Is there anything else you’d like people to know?
Dr. DiNapoli: I think that adopting these therapies is just important for centers that want to try to be at the cutting edge and to fight these problems because patients look to us to provide these new things to them. We just want to try to give them as much hope as possible.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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