Episode Transcript
Interviewer: If you or a loved one has been diagnosed with a meningioma, you might be wondering what that means, what you need to do about it. Is it worth having it removed? They are the most common brain tumor, and most of the time they're benign and asymptomatic. But they don't always stay that way.
Dr. William Couldwell is the chair of the at 91麻豆天美直播. Dr. Couldwell, first, what is a meningioma?
What Is a Meningioma?
Dr. Couldwell: A meningioma is usually a benign tumor that occurs from the covering of the brain. Now, the covering of the brain covers the entire brain, and it's attached to the inside of the skull. It's called the meninges. It's sort of like a thick piece of paper in thickness, and it's attached everywhere on the skull and inside the spinal canal where the spinal cord runs. They rise from the meninges, hence the name "meningioma."
Interviewer: So is this forming then at the base of the skull where the spinal cord and the brain kind of are close to each other?
Dr. Couldwell: Yeah. So the reason that we differentiate them as skull base versus non-skull base is the following. The skull base is a complicated area of your head. It's where all the nerves and the arteries . . . so all the nerves that serve things like vision, moving your eyes, facial sensation, hearing, swallowing, etc., they all traverse the base of the skull. And then the arteries that feed your brain, the two carotid arteries in the anterior compartment and the two vertebral arteries, enter at the region of the base of the skull. So that makes it a much more complicated area to have any type of tumor, especially if you have a meningioma.
If they occur in the convexity on the top of your head, they're usually not too much of a surgical challenge. But when they occur at the base of the skull, they're more of a surgical challenge because the technical difficulties of dealing with them adjacent . . . they can surround the nerves and the arteries. Then we have to use a lot of different techniques to remove them in that location. Special approaches, sometimes we have to disconnect the artery and reconnect it again, that type of thing.
How Common Are Meningiomas?
Interviewer: And how common is this type of a tumor, a meningioma?
Dr. Couldwell: It's one of the most common tumors found in the brain, or intracranial, put it that way. About a third of the brain tumors that we diagnose every year are meningiomas. So I think, together with pituitary tumors, they represent the majority of tumors that are found.
And so it's quite common in the general population. They're more common in women. And the reason we think that is because women, during their reproductive life, have hormonal pulses every month of estrogen, progesterone, and then during pregnancy, and this can stimulate the growth of these tumors. We know that when we grow the tumors in tissue culture, we can stimulate the growth with these types of hormones. So they do occur more frequently in women.
And we find them quite frequently in older people who didn't know they have them. We call those "incidental tumors." And they're found when people get scans for other reasons, a headache, maybe they fell on the ice and hit their head, or a car accident. And we often find meningiomas that they didn't even know they had.
Interviewer: And just because somebody has a meningioma doesn't necessarily mean anything needs to be done about it, right? Isn't it usually when they become symptomatic that you become more concerned?
Dr. Couldwell: You're absolutely right. And in general, I always teach my residents and fellows that we don't usually treat incidental meningiomas. But we do follow them. And so we usually scan them with serial scans and make sure that they don't grow to a size that they would become a problem. If they're symptomatic or if they become symptomatic, we usually then consider treatment.
Interviewer: So it sounds like that you would have two different types of patients that might come to you with a meningioma. One that would have an incidental meningioma that had been diagnosed for some other reason because of other scans that had been taken, and you would work through with them what that meant.
Dr. Couldwell: Correct.
Interviewer: And what they would do. I think you just explained that. Is there anything additional for somebody who has an incidental meningioma that you would tell them?
Dr. Couldwell: No. What we do is we follow them. If the scan is growing very slowly and the patient is older, sometimes we still recommend just following it. We make a calculation to sort of see if we can determine whether the tumor will need to be treated in their remaining lifetime.
But oftentimes, in postmenopausal women, the growth may slow and may become dormant after that time. And so we often see tumors in older women that don't grow much.
In all patients, we follow them with serial scans. And in some of them, they go on to treatment, but a lot of them we can just follow them.
Meningioma Symptoms
Interviewer: And then the other type of patient is a patient that has a meningioma that they found out because they were experiencing some sort of symptom. So what type of symptoms would lead somebody to go to a physician that would lead to this diagnosis?
Dr. Couldwell: So, when they occur in the convexity of the head, they can grow often much bigger because the small tumors tend to be tolerated in that location. But when they push on the brain in significant ways, they could have some weakness or some numbness in certain parts of their body.
And then when they occur in the base of the skull, as I mentioned, they're more of a challenge because they can start to impinge on the nerves that traverse the base of the skull.
And so, oftentimes, I see many patients with visual problems from meningiomas because the tumor is growing and compressing the optic nerves. The optic nerve is very sensitive, and usually it's a very small tumor that can just be in a strategic location but can cause problems with the optic nerves or the nerves that move the eye.
Oftentimes, if the tumor is growing next to the nerve that serves hearing, for instance, it's a very sensitive nerve and they can notice hearing loss as well.
So it depends on the location. It's the real estate rule. It depends on the size and the location of the tumor. Often, tumors that are not that big in size can cause problems in the skull base.
Progressive Symptoms: Sight, Swallowing, Hearing Loss
Interviewer: So some of these symptoms . . . I mean, is this a pretty difficult thing to diagnose? Because if somebody is older, your sight is going to start going. Your hearing is going to start going. Or are there some telltale signs that you know that this is pretty good chance it's a meningioma?
Dr. Couldwell: Sure. I mean, I think you mentioned the fact that these can be a very broad range of symptoms because it depends on where the growth is occurring. But if you have unilateral problems, say you're starting to lose vision in one eye or hearing in one ear or difficulty swallowing, for instance, and if it's just not a general high-frequency hearing loss that we see in older age, then these can be clues.
So asymmetric symptoms, I think, is a big one, and then progressive symptoms. So it's often not acute symptoms. They're often progressive.
Interviewer: I would imagine a patient would go to their primary care provider first with these types of symptoms. And then would the primary care provider be able to determine these symptoms, suggest some imaging, and then is that how they would end up talking to you, Dr. Couldwell?
Dr. Couldwell: Yeah. Most of the patients that get referred in have had a great work-up by their primary care or their internist. They'll have a scan that's been ordered by the primary care doctor. And the imaging is so good nowadays. If they get an MRI, that will detect usually a significant meningioma. It would be rare that a significant meningioma would be missed on a modern MRI. So that's the most frequent way that I see them diagnosed.
Meningioma Treatment
Interviewer: And then when a patient comes to you with a meningioma that is causing symptoms, what are the types of treatment options you start discussing?
Dr. Couldwell: So there are always three general treatment options that we talk about with meningiomas.
- First is observation, and we've talked about that.
- The second is surgery, and we decide whether we wish to operate based on the age of the patient, the symptoms that they're having, the size of the tumor, and its location.
- And then the third option for management would be radiation treatment. There is no good medical therapy for meningiomas. We can't give them a pill and have the tumor shrink away at this time. There are lots of studies going on, but there's nothing clinical utilized right now.
So the radiation we often reserve for meningiomas in difficult places in, say, older patients that have less of a lifespan to live with the tumor. And there is risk of radiation and they may not be immediate but they may be down the line. We'll follow the patient with the tumor and the scan for the remainder of their life.
So, if somebody's diagnosed with a meningioma, whether they have a surgical removal or they have radiation, we follow them with serial imaging for the perpetuity of their life for the simple reason that you can have recurrence. You can have recurrence after surgery, and you can have recurrence after radiation. So we monitor them very carefully.
Usually, if it's a benign meningioma, which most of them are, we scan them once a year and follow them up in clinic once a year.
Interviewer: Okay. And "benign," of course, meaning non-cancerous, which would be a concern of a lot of people. Any time you hear "tumor," probably the first thing you want to know is, "Is this cancerous?" And meningiomas tend not to be, huh?
Dr. Couldwell: That's right. They're not cancerous, but as I say, you can have a benign tumor in a difficult location and that really explains the problems with some of these meningiomas.
Interviewer: How much of weighing goes into determining the symptoms a patient is experiencing versus perhaps what the side effects of the treatment might be?
Dr. Couldwell: So what we're always comparing is the risk of treatment versus the risk of the disease, which I think is the question you're asking. And when we're weighing options for management of skull base tumors, that's a very important concept because we don't want to cause more deficit with removal of the tumor than the tumor is causing. So we'll weigh in the location of the tumor, the specifics of the tumor, the age of the patient, and how fast the symptoms are progressing to really determine the best possible option for maintaining function as long as possible.
Some of these tumors, you can imagine, can invade into the carotid artery. They can invade into the region of the cavernous sinus where the nerves run that move the eye. And so they really preclude complete treatment without causing new deficit.
Meningioma Surgery
So, in those cases, we'll manage them with observation or with radiation and watch them. And then if they fail those treatments, we'll consider a more aggressive surgery.
But in general, we don't like to add any treatment that will cause more immediate loss of function. So we'll wait and watch the tumor and help them manage to try and preserve function as long as possible.
Interviewer: And what are some side effects of the surgery that you're looking at when you're making that weigh?
Dr. Couldwell: So we're always weighing the risk of surgery. You could have risks of cranial nerve deficit, which are nerves that move the eye, or sensation to the face, or hearing, or vision, versus the natural history of the tumor. And also the risks of radiation, because radiation can cause problems with the nerve function as well.
And so we weigh each of these cases individually. And if they're complicated cases, we present them at our tumor board. The neurosurgeons and the radiation therapists will get together, and then we'll map out the plan for the treatment for the patient that will give them the best tumor control with the fewest symptoms.
Interviewer: And when you decide that surgery is the proper course of action, give me kind of an insight of what that looks like. Is there a lot of planning that goes in on your part as the surgeon to figure out how to approach that before the surgery actually happens?
Dr. Couldwell: Yes, there certainly is. We spend a lot of time looking at 3D renderings of the images and determining where the tumor is and how extensive it is and the location of the tumor and whether it envelops the nerves or how it is pushing the nerve in one direction or another.
And then we choose a specific approach to the base of the skull that's designed to really provide the best advantage to remove the tumor with causing the least disruption of nerve function.
So we try to approach the tumor by removing more bone in one direction rather than having to manipulate the nerve or retract the nerve.
And so all of these are very complicated approaches. We've refined them over many years, and we're still refining them, but this is modern skull base surgery, so it's a highly technical aspect of neurosurgery.
Interviewer: And then how invasive is this type of surgery?
Dr. Couldwell: We have some operations where we'll do a very invasive operation. We'll remove part of the skull or the orbit and the eye and that type of thing in some cases. But those are usually cases with refractory or recurrent tumors that have had all sorts of therapy, radiation treatment, partial resections, and have failed everything.
So we'll usually start out with very minimally invasive surgeries. And we use smaller openings. We use endoscopes, that type of thing. We can come through the nose, through the face in many cases, or come down lateral and use a smaller opening to try and achieve sort of keyhole surgery where we remove the tumor and we disrupt the neurological tissue as little as possible.
And so we'll come through all different approaches laterally and anteriorly to reach these tumors, to try and achieve the best approach to the tumor without having to retract or manipulate the nerves in the brain stem.
Interviewer: And is the goal always complete removal of the tumor, or sometimes is the goal just to get enough of the tumor out that gets rid of the symptoms?
Dr. Couldwell: So, in general, we try to remove the tumor, and we try to remove the tumor in everybody if we can. But if we feel that the tumor removal is going to be associated with too many complications, in some cases we'll do a decompression and then treat the remaining part of it with radiation.
We've got very sophisticated radiation machines nowadays that can tailor and sculpt the radiation dose to the shape of the tumor in three-dimensional space and try to reduce the radiation dose of the surrounding tissue and concentrates the dose on this complex three-dimensional object.
When to See an Expert for Meningioma Treatment
Interviewer: And if a patient is trying to determine who should remove their meningioma, how could a patient start to make that decision?
Dr. Couldwell: I think there are a lot of support groups online. I always recommend that they try to find experienced people and experts in the field. If you have a complicated tumor, you wouldn't go to a generalist. You'd go to a specialist for that. And that's across all of medicine.
We have skull base surgery as a unique specialty. There are a number of us around the country that really focus on skull base tumors and meningiomas in particular. And so you really want to find somebody who's got a lot of experience and published experience and they've published their outcomes with the management of these tumors in different locations. And usually, with enough research, you can find those people.
Interviewer: So when you say "published," they have actually published papers on different challenging meningiomas and how they approached it, is that what you mean?
Dr. Couldwell: Yes, exactly. And often they're not lay publications, but they're professional publications. This is how we educate ourselves as a specialty. But those are all referenced online, and you can find out with the simple search engines the experience that people have had and the cases that they've done and the outcomes that have been published.
I think it's important that you really find experts in this particular area because this is a very complicated part of neurosurgery.
Interviewer: Yeah. So find the experts that specialize in meningioma and skull base surgery, and then find out their outcomes, the different cases they've had to take on in the publications.
I've heard in the past sometimes you just look for somebody who's done a lot of these surgeries, which is always a good metric. Is it a good metric in this instance?
Dr. Couldwell: It is. I mean, I'm a firm believer in what we call the volume-outcome relationship. The more you do, the better you get at it. And skull base surgery is no exception. It's the same in any aspect of surgery.
This is the real benefit of having a larger department with a lot of specialization in each area. You get experts in their respective field. And this is how the field gets moved forward, is by people focusing their practice and making contributions in that specialized area.
Interviewer: And what's kind of a minimum number of procedures that you would be looking for?
Dr. Couldwell: These are fairly common tumors. I do about 100 a year here. But I'd like to see somebody with the experience of . . . before they start doing complicated surgeries, I'd like to see them with a lot of experience. We have fellows, for instance, that are fully trained neurosurgeons that come and spend a year and they really focus on skull base surgery and they get a refined experience just in this one area of neurosurgery.
I mean, to feel comfortable about a surgeon operating on a specific skull base tumor, it'd be nice to see them have experience with dozens or hundreds of cases.
Interviewer: And how important is the team in treating meningioma that surrounds you?
Dr. Couldwell: I think you're only as good as your weakest link. And I think it's important that you have a group of people that's really focused on taking care of these patients. Oftentimes, we'll work with the ENT specialists when we do these lateral approaches through the ear, for instance, the hearing bone, to reach these tumors. And so it's nice to have a skull base team.
And the OR that's capable of managing these tumors, sometimes we use intra-operative imaging, like with an intra-operative MRI, to help remove the tumors as well.
And then post-op care is important. So you need an ICU that's familiar with taking care of these patients and the specific complications that they get. They can get complications from vascular injury. They can get complications from nerve injury. They can get complications from leaking of the spinal fluid. And what that is, is our brains are packed in saltwater and sometimes we have to open up the base of the skull, remove the tumor, and then we have to close the base of the skull so that the water doesn't leak down into the nose or through the ear. And you need techniques and methods to close those and then also to manage them post-operatively and recognize them as a complication.
Interviewer: Do you have any final thoughts for a patient who is listening to this and, obviously, has some concerns about their meningioma? What would you say to that person?
Dr. Couldwell: I mean, I must admit we see lots of patients every year. I operate on about 100 patients a year, but I see several hundred with these tumors. And the real issue is determining which ones need to be removed or will need to be removed and the ones that can just be monitored.
Oftentimes, of course, when the family doctor or the internist orders an MRI and the patient is diagnosed with a meningioma, they don't know whether it's a difficult one or a simple one or one that can be watched. But we do have a mechanism to sort of look at them and let them know and say, "Listen, we can just watch this. We'll repeat the scan in six months and then yearly thereafter and then watch it." And that's often a lot of peace of mind for people.
We have a frequently asked questions sheet that we give to the patients, and we have websites that we point them to, including our own, that have the information on meningiomas. And so, oftentimes, it's just counseling with the experts and the teams that can really give them the best advice.
When Should a Meningioma Be Removed?
Meningioma is a common type of skull base tumor and typically non-cancerous. However, they can still cause symptoms depending on their location and how they grow. Neurosurgeon William Couldwell, MD...