Transcription:
Chordoma: En Bloc Resection and Other Management Strategies

Andrew Wilner, MD (Host): Welcome to Better Edge, a Northwestern Medicine podcast for physicians. I'm Dr. Andrew Wilner. And today we are discussing the management of chordoma with Dr. Jean-Paul Wolinsky. Chordoma's are rare primary malignant spine tumors that occur in one out of 1 million people. As rare as chordoma's are, neurosurgeons with the extensive training and experience required to remove them are even more uncommon.

Dr. Jean-Paul Wolinsky of Northwestern Medicine is one of a handful of surgeons in the country capable of performing en bloc chordoma resections. Dr. Wolinsky is a Professor of Neurologic Surgery and Orthopedic Surgery, Vice Chair of Strategy and Operations in the Department of Neurological Surgery and a member of the Lou and Jean Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University at Northwestern Memorial Hospital.

Dr. Wolinsky is joining me today to discuss his unique surgical technique, as well as investigational therapies for chordoma. This is Better Edge. Welcome Dr. Wolinsky.

Jean-Paul Wolinsky, MD (Guest): Thank you Andrew for having me.

Host: Yeah. It's definitely our pleasure to have you and teach us about chordoma's. Let's start with that. What is a chordoma?

Dr. Wolinsky: Well, so like you said in the introduction, chordoma's are very rare tumors. We think the incidence is about one in a million. And what that means for patients is that most patients, when they see somebody for their chordoma initially are probably seeing somebody who's never seen a chordoma, let alone heard about one.

So in my experience, it seems that maybe a neurosurgeon will see one in their entire career and probably even less than that actually operate on any of them. Many years ago, probably I'm dating myself, but probably 30 years ago or so, at that time, people would consider these tumors to be fairly benign. And the reason that people probably thought this was that when the surgeons would operate on these tumors, they would operate on them in a way or fashion that's very similar to what we would do with regular brain tumors, where we tend to go intralesionally in these tumors, where we go into the tumor itself and suck the tumor out. And the neurosurgeons at the time would think, well, this is fairly straightforward. The tumor sucks out and tends not to be that bloody and the patients would do okay.

And the pathologist would look at these specimens and look at the cells and the cells would look fairly bland and not aggressive looking like some of our other sarcoma or other types of tumors. And these patients would go on their way. And the majority of these patients would recur. And if you're only seeing one in a million patients who are one of these patients in your career and that patient recurred, the patient probably wouldn't come back to you.

And because technology isn't where it is today with communication, people didn't realize they were necessarily doing a bad thing for their patients. And these patients would recur and recur and recur and eventually metastasize to other places. Now we know better that these tumors are actually malignant tumors.

And when we look at these tumors, in a simplistic way, you can think of tumor treatment as three different ways of treating something or a combination of treating them. One option to treat somebody as to treat him with chemotherapy, one option to treat somebody is to treat them with radiation therapy. And the third option is surgery. We know what intralesional surgery does. And so that's not really a great option for patients. Unfortunately, with chordomas, we haven't found a chemotherapy that works yet. In some patients where they might have a recurrent tumor or they have a tumor that's unresectable, we may consider experimental chemotherapy, but we're really trying to best educated guess as to what might work.

And unfortunately, really most things haven't worked at all. Radiation therapy is an option for these patients to a certain degree. Almost anything can be killed with radiation if you give a high enough dose of radiation. With our sophisticated radiation techniques, we can give up to about 70 gray of radiation to a tumor, which is a very high dose of radiation.

That's probably half of what we need to actually kill that tumor. Probably need somewhere close to 140 gray to kill those tumors. And if you were to do that to somebody, you'd probably kill that tumor, but you would turn them to charcoal. So it's probably not a great option for them. Going back to the surgical option of what we have found though, is if we take a tumor out in one piece and do an en bloc resection with a negative margin, meaning that the tumor doesn't come through the margin of the resection, then we have the best chance for disease free survival and cure.

And that's what we aim for with these patients. When we look at where chordoma's occur in the, body, they occur in the skull base or the clivus and down in the sacrum most frequently. But they also occur on what we call the mobile spine. So the part of the spine that moves. In the clivus or the skull base because of the architecture in that area, and the very important nerves in that area, en bloc resection is really not feasible. It's probably been three cases of en bloc resection of a clival tumor, where the tumor was very small and they can get completely around it. But that's not considered the routine treatment for these type of patients with clival tumors.

Unfortunately, there, we're stuck with intralesional resection and radiation therapy as our mainstays of treatment. Down in the mobile spine and the sacrum, it's a different story. And those areas of the spine, we try to take these tumors out in one piece and to do that, we do what we call an en bloc resection.

And to do that, we might need multiple different operations to get around this tumor to carefully separate the spinal cord or the nerves away from the tumor, trying to preserve as much neurologic function as possible, and then deliver the tumor away from the spinal cord or the critical structures. When we do this, you know, obviously we have to take apart the spine to get these tumors out.

And so these are fairly destructive procedures, as far as the spine is concerned and we need to reconstruct the spine afterwards. In the sacrum, this would require a lumbopelvic reconstruction and the mobile spine, it would require instrumentation with rods and screws and cages to hold the spine together. All these things that we place into patients are there so that we can reconstruct people to get them back to their normal lives.

And with these patients though, after they've had their resection, then we need to follow them life long to make sure that the tumor's not coming back, so that we can really understand are we doing the right thing for these patients. And if the tumor comes back, what's the next step, as far as treatment. When you look at these types of tumors, they occur in sort of a bi-modal fashion, some early and some late. Early can be as early as several months to a couple of years after surgery and late can be 5, 10, 15 years after surgery. So in my mind, we're offering surgery to the patient. We're offering en bloc resection to a patient, an ideal operation with a negative margin resection is to offer them a long-term disease free survival, and hopefully cure. But the only way I'm able to tell a patient that they've been cured is if one of us has gone through their entire life and died for other reasons later in life, then we know that the tumor hasn't come back.

Host: Well, thanks for that explanation. I have two questions. As a neurologist, I'm curious, what would the typical presentation be of a patient? In other words, when should I suspect that a patient has a chordoma?

Dr. Wolinsky: That's a very difficult question because these are slow growing tumors. And so with being slow growing tumors, the nerves can be slowly pushed or the spinal cord can be slowly pushed or even the brainstem can be slowly pushed to one side. Tumors in the sacral region can grow to quite enormous sizes. And it's not uncommon for a sacral chordoma to be the size of a softball or even a football. Even with such large tumors, it's amazing how sometimes these patients have very little to no neurologic deficits, meaning no changes in their bowel, bladder, or sexual function, or weakness. Likewise tumors within the mobile spine can grow slowly and put pressure on the spinal cord and displace the spinal cord. And it can take a long time for patients to display symptoms of myelopathy or weakness. Majority of these patients really present with pain. It might present with back pain, it might present with radicular pain, or they might present with sacral or buttock pain.

So in certain ways they can be very common types of symptoms that all of us get all the time. Now, these tumors are very rare, so we don't suspect everybody with back pain to have a chordoma. I sometimes wonder about it myself. As, we get older, we always get more and more back pain. Right. And when I see these patients with chordomas, you always wonder, do I have one of these things myself causing the pain, but that's luckily not usually the case.

Host: Well, that's very helpful, Dr. Wolinsky. Now because the patients are so unique in their presentation and size of the tumor and location. And you do have the several modalities that you described of chemotherapy, radiation therapy, intralesional removal by neurosurgery, and then more definitive en block resection; when you do have a patient, how do you decide what to do?

Dr. Wolinsky: Yeah, the first step is really establishing the diagnosis. So, there are many things that can look like chordoma on MRI scans. Typically on an MRI scan, the chordoma will have a T1 hypointense signal, the T2 hyperintense signal, and the T1 with contrast images may or may not enhance. Frequently we'll get PET scans on patients, but these tumors tend not actually to be, FEG positive on PET.

So they might not light up on PET. If they do light up on PET, it's a useful scan to have for following these patients in the future. But if they don't light up a PET, it doesn't say whether or not they have, or do not have a chordoma. So, for me, the most important thing as the initial step is the biopsy. The biopsy is important so that we can understand exactly what the tumor is.

I've had several patients come to me with the diagnosis or presumed diagnosis of a chordoma, and we do the biopsy and they might have something else like multiple myeloma, lung cancer, some other type of tumor. And so it's very important because the type of operation that we're doing is quite extensive. And you don't want to put somebody through that operation if that's not really the indicated operation for them.

And so the biopsy becomes paramount. How we do the biopsies are also critical because we don't want to sacrifice that patient's chance of potential disease free survival and cure. So when we plan a biopsy for a sacral chordoma, we plan the biopsy to go through a transsacral route, coming through the backside, coming through the skin, coming through the bone and into the tumor.

So that if some of these little tumor cells get cheated into the biopsy track, that biopsy track can be removed with the tumor. With today's needle technology, it's very unlikely that we're going to see the biopsy track with tumor. We still want to be able to minimize that if possible. We don't want to try a transrectal route and contaminate the rectum with the tumor. Even though this might be the easiest way to get the biopsy, it would make it really impossible, if not impossible to treat these types of tumors.

Host: Well, it sounds complex and maybe a little bit suboptimal sometimes. So tell us a little bit about the future. You're currently the principal investigator on a grant funded by the Cancer Research Institute, exploring the immunology and potential immunotherapy of chordoma. Can you tell us a little bit about that work and how that might compliment the standard therapies?

Dr. Wolinsky: So really the brains behind that, and I have to give credit to these people because they're really the smart investigators of trying to figure this out are Catalina Chang and Jason Miska, who are PhD's researching this project. So we have been working together for several years and talking about chordoma's and their research primarily had been in glioblastomas or brain tumors and immunological therapies for these types of tumors.

And one of the things about chordoma that tends to attract investigators and surgeons towards them is that they're very unique and rare, and the patients are very unique and rare. And one of the things that we were talking about is that nobody really understands the immunological environment that these tumors sit in. And distinct from what we see with our brain tumors, these tumors are not in this very privileged space beyond the blood-brain barrier. So chemotherapy and immunotherapy and different types of treatments can actually penetrate into these tumors essentially. So they, have more conventional options for these tumors, even though we haven't yet found out the chemotherapy option for them.

So the thought behind this is if we can characterize the immunological environment that these tumors are in, perhaps we can find a better treatment, a better immunotherapy or some other treatment that can help these patients and in certain ways put me out of a job so that I won't have to do any of these en bloc projections anymore.

Host: So, what do you think, is it going to be ready next year? This immunotherapy, or do we have to wait for sort of clinical trials and the magic antibody?

Dr. Wolinsky: Unfortunately, I don't think it's going to be ready for next year. It would be great. We are trying things all the time, but time is required to figure this out. And although we've made amazing strides from the scientific community for just developing vaccines for COVID in such a short period of time, really studying these tumors and understanding what therapy is going to be an option for them, really takes time.

Fortunately, for patients, these tumors are very rare, but also unfortunately for tumor, patients, these tumors are very rare, which means that for our tumor bank, which is operated by one of our, pathologists, Dr. Craig Horbinski, for our tumor bank to have enough of these tissues for us to really study them requires time.

And these tissues do need to be handled carefully so that they can actually have these tissues to test for the microenvironment that they're looking for. So I don't think that next year will be the answer for the cure, but hopefully.

Host: Well right now you do have a pretty, well-established framework with the tumor board and multidisciplinary discussions to evaluate and come up with a plan for each patient, isnt that right?

Dr. Wolinsky: That's true. So every patient with a chordoma, I think is unique. And every tumor location is a little bit unique as well. So, every patient needs a pretty much a tailored operation for how we're going to get that tumor out and also a tailored plan for how we're going to reconstruct the spine.

Additionally, we have a group of oncologists, neuro-oncologists, plastic surgeons that are going to think about how we're going to get this patient through their other treatments, because sometimes the en bloc restriction might not be enough for them. They might need radiation therapy in the future. They might need immunotherapy in the future. They might need to experimental chemotherapy in the future. And so we want to prepare the patients ahead of time for understanding this. And we also want to prepare ourselves to understand where the pitfalls might be and what we can do to optimize their outcomes.

Host: Well, that's great. Well, Dr. Wolinsky as we wrap up, is there anything physicians should keep in mind when referring or treating patients with chordoma?

Dr. Wolinsky: Well, one of the things that, when I was a resident, you always wanted to tackle the biggest, most difficult cases. That's very important to keep in mind is that these cases, aren't cases, they're cases and they're patients and patients really want the best treatment for them. And if you've never seen one of these cases, if you've never performed one of these operations, you really aren't the person that's probably qualified to do these treatments. And so I think that these patients deserve referral to a specialized center. And these tumors aren't the fastest growing tumors in the world, so that patients have time to travel. These patients tend to be the most educated patients.

They know all about their tumors. And they should have the opportunity to have the best treatment for them. So I think it's important if one of these tumors is discovered, that they get the patient to the right place so that they can have the best treatment outcomes.

Host: That sounds like a great advice. Dr. Wolinsky, this has been very informative and want to thank you for sharing your expertise on the management of chordomas.

Dr. Wolinsky: Thank you very much for having me.

Host: And that wraps up this episode of Better Edge, a Northwestern Medicine podcast for physicians. To refer your patient, please visit our website at breakthroughsforphysicians.nm.org/neuro. Please remember to subscribe, rate and review this podcast and all the other Northwestern Medicine podcasts. For updates on the latest medical advancements, breakthroughs and research, you can follow us on your social media channels. I'm Dr. Andrew Wilner. Thanks for listening.