Neurosurgeon at Allegheny Health Network, Matthew Shepard, MD talks about treating brain tumors with a new device called GammaTile brachytherapy.
Interview conducted by Ivanhoe Broadcast News in 2023.
Can you tell us how many patients are affected by re-occurring brain tumors?
Shepard: Primary brain tumors are a relatively rare diagnosis for most patients. It is estimated that 30,000 patients a year are diagnosed with a benign or malignant brain tumor. For patients with malginant tumors, they have high rates of recurrence and can negatively impact patients quality of life and longevity.
If you don’t know how many patients specifically, how widespread is this problem, is it something that’s common?
Shepard: So primary brain tumors are very rare and affect a very small subset of patients throughout the country. With that said, they have a significant impact on the quality of life and the longevity of life for patients who they affect. So in those patients, we oftentimes need multimodality treatments in order to help them live better and live longer.
Understood. So is it often you find these in older patients or younger patients?
Shepard: Primary brain tumors can affect older adults and younger adults alike. There are a wide variety of underlying pathologies that can cause a brain tumor. The most common type of brain tumor that is cancerous actually doesn’t arise from the brain tissue itself – it actually arises from other sites of the body, such as a lung cancer, or a colon cancer, or a melanoma and these can typically affect older adults.
When we’re talking about reoccurring brain tumors, why do they come back?
Shepard: Well, the answer to that question depends on whether or not it is a primary brain tumor, such as a glioma or a brain metastasis. Brain metastases are cancers that spread to the brain from other cancers, like a lung cancer, melanoma, or other cancer from somewhere else in the body. With regards to primary brain tumors under the umbrella of gliomas, for example, these are tumors that even though we can see them on an MRI scan, oftentimes we’re really just looking at the tip of the iceberg. When I show a patient their MRI scan and show them their brain tumor, oftentimes what we’re looking at is it will be called the enhancing portion of the tumor. But we know that these tumors oftentimes infiltrate normal parts of the brain that we can’t see as abnormal when we’re taking them to the operating room. Now when I take a patient to surgery for the first time, I have a lot of interesting tools in my tool kit that I can use to try to remove not only the tumors that I can see on the MRI scan but some of the tumors that can be invisible, on MRIs. Despite that, the brain is a sensitive organ and we can’t just remove significant, functional portions of the brain during surgery. And so oftentimes, even though I remove everything that is abnormal and potentially push the boundary to try to remove things that we can’t see on the imaging, there’s oftentimes tumor cells that are left behind and it is these tumor cells that we can’t see that oftentimes are the seeds that can grow back into recurrent tumors.
How are they typically treated?
Shepard: So brain tumors, oftentimes are treated with maximal safe resection and depending on the underlying pathology, potentially chemotherapy and radiation thereafter. Brain metastases are also treated in a similar way in those cases, we oftentimes reserve surgery for patients who have very large brain metastases, or brain metastases that are causing significant symptoms to patients.
When you have a patient that you’re treating over and over again and removing their tumors and they’re coming back, what toll do you see that taking on a patient and their families? What does that look like for them?
Shepard: There is no doubt that being diagnosed with a brain tumor or having a family member or someone who you love and care about being diagnosed with a brain tumor is one of the worst things that one can go through. So bringing patients back to the operating room every on multiple occasions, undergoing recurrent chemotherapy and radiation treatment, that takes up a tremendous amount of time and keeps patients away from doing the things that they ultimately care most about. So our goal is to always try to give the patients the best outcome so that they don’t have to keep undergoing chemotherapy, so they don’t have to keep undergoing radiation therapy. When patients are diagnosed with a brain tumor, these are not cancers that just occur in someone’s body, they’re occurring in the area that makes them who they are, that makes them independent. That controls their ability to speech, write, communicate, or move their arms or legs. So when tumors keep coming back, these functions can get threatened and significantly impair someone’s quality of life.
So that leads us into GammaTile. What is GammaTile? How does that work?
Shepard: So the fancy name for GammaTile is Brachytherapy. And what that means is, at the time of surgery, we implant little tiles that are implanted with some radiation seeds that emit a low dose radiation over several months. And what that means is that, like I was talking about earlier, is that any tumor cells that are left behind at the time of surgery can be killed off by the radiation that is emitted by these tiles that we implanted at the time of surgery.
And when you say tiles, how big are we talking here?
Shepard: I tell most patients that these tiles are about the size of a postage stamp. I tailor the number of tiles for each patient as everyone’s tumor is a little bit bigger or a little bit smaller, and the cavity that’s left behind is variable so we make that determination based off a pre-operative imaging.
So you mentioned how it works, can you get a little bit deeper into that and expound on how long it works, how long it lasts, how long does it stay on the brain?
Shepard: So when put these tiles into the brain, they are going to stay there. The tiles dissolve over time. Going back to physics from college or from high school the duration of the radiation treatment is really a function of the radioactive seed implanted in the patient. The half life for these seeds is usually around nine days. And so over several weeks there is progressively less and less radiation dosing delivered to the patient, such that by two months after the implantation, there’s relatively negligible amounts of radiation being admitted into the brain.
In the tiles, you said they stay in there but do they dissolve at some point or they just in there?
Shepard: They’re in a collagen matrix and eventually that collagen will eventually get reabsorbed, but the radiation seeds will stay in place.
When we put out the press release, you describe putting those Gamma tiles in as building a house in the patient’s head. What do you mean by that?
Shepard: So when we plant the Gamma tiles, we’re really just walling off the surgical cavity. When I take a tumor out, there’s a small little cavity that’s left behind and I just tile that cavity with these tiles in order to get maximum safe radiation coverage to the tumor, or any tumor that could be left behind.
Is this safer than traditional radiation?
Shepard: Well, it is a form of radiation. And overall when I think we’re looking at this, there are some types of toxicity that can occur from any type of treatment. With that said, GammaTile has been shown to be extremely safe and very well tolerated in patients. And when we look at the studies looking at the progression free survival and overall survival for patients with recurrent tumors that have underwent Gamma tile therapy, we’re seeing progression free survival and overall survivals that are almost a year or greater. And when you compare that to the normal expected outcomes for patients who have recurrent brain tumors, that is really moving the needle in the right direction. So overall, this is a pretty well safe and tolerated therapy for most patients.
And so you called this a game changer, can you get into more as to why, and maybe even talk about how there might not be traditional radiation symptoms like your hair falling out or whatever the case may be?
Shepard: So this is localized radiation therapy that is delivered to patients while they’re recovering from their surgery. So with conventional radiation therapy, you have to come back to the hospital multiple times a week. There can be deleterious consequences with hair loss depending on the type of radiation therapy that you receive. With Gamma tiles it’s as if you set it and you forget it because you you immmediatley receive the radiation therapy once it is implanted. The radiation is being emitted over several weeks to months while you’re recovering from your- from your surgery, that you’re getting 100% complete patient compliance with this treatment. And ultimately, this is a type of therapy that we can give to patients who have already failed traditional radiation therapy. Before GammaTile, if you had a tumor come back and you’ve already undergone conventional radiation therapy, it would be very unlikely that you’d be a good candidate for more radiation therapy. But because this radiation therapy has limited brain penetrance and given over a very long time, it is a very reasonable option for most patients. Even if you’ve received radiation therapy before, you may be a good candidate for Gamma tile.
Who’s a good candidate for this, who is not a good candidate for this?
Shepard: So we’re still learning more and more about GammaTile even as we speak. So for me, the ideal patient for GammaTile at this time would be patients who have a recurrent malignant brain tumor or a patient with a rapidly recurring benign tumor. We are currently looking at to see whether or not Gamma tile therapy is actually superior to conventional treatments but those are ongoing clinical trials that it will take some time to fully answer that question.
Are you able to tell us a little bit more about Anthony Parise’s tumors, where they were, how many he had?
Shepard: So Mr. Parise, who is one of my favorite patients by the way, and one of the nicest guys I’ve ever met, he had a lung cancer that has been treated. The only spot where he has had any sites of disease currently are in his brain. Originally his tumor was extremely small and was treated with stereotactic radiosurgery. Despite that radiation treatment, his tumor grew and came back and I had to remove it. It came back again we did more radiation. Despite that, it grew more. So now we’re in a situation where we have a patient who has lung cancer, but the only spot where they have the lung cancer on their whole body is in his brain. And he’s already failed one surgery and two rounds of radiation. So the question becomes, what do we do next? And he’s pretty much at the end of the line here, unless I can get that tumor out and prevent it from coming back. And so GammaTile was the next option for him.
How has he done with GammaTile? What has this meant for him?
Shepard: So he’s only a few months out right now, but so far so good. The tumor on his last MRI scan was being kept at bay. We were able to get the whole tumor out on his last surgery and the GammaTile and so far there has not been any recurrent on his MRIs.
When you say he was at the end of the line without GammaTile, was he out of options?
Shepard: Well, surgery was certainly another option on the table but, when you keep doing surgery and things keep coming back, is that going to be the definitive thing the next time around? I couldn’t be certain so this allows me to give a little bit extra line of defense to try to fight that tumor.
How big were his tumors on his brain?
Shepard: His original tumor that we treat with radiation therapy was smaller than my thumbnail, so pretty small. The tumors when they became bigger were several centimeters in size and located in part of the brain that controls his visual processing.
It’s still too soon to really tell long term but in the short term, Anthony seems to be doing well, right?
Shepard: Absolutely.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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Sarafina Brooks James
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