The GPS of Brain Surgery

MD Anderson Cancer Center
Date: 04-01-11

 

Lisa Garvin: Welcome to Cancer Newsline, a weekly podcast series from The University of Texas M.D. Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment, and prevention, providing the latest information on reducing your family's cancer risk. I'm your host, Lisa Garvin. Today, our guest is Jeff Weinberg. He is an Associate Professor of Neurosurgery here at M.D. Anderson and I like to call him the guru of intraoperative MRI here at M.D. Anderson. Welcome Dr. Weinberg.

Jeffrey S. Weinberg, MD, FACS: Nice to see you Lisa.

Lisa Garvin: About five years ago, we were talking about bringing intraoperative MRI to M.D. Anderson. First of all, let's tell people what it is exactly.

Jeffrey S. Weinberg, MD, FACS: : So, the intraoperative MRI program with the room that we have, the Operating Room has an MRI actually in the Operating Room. And the benefits of that are tremendous for us so it gives us the ability to actually get an MRI scan during the surgery. So, as we are removing the tumor, we know exactly how much we removed, we know exactly how much remains, so we know the clinical structures that we don't want to damage. We know their location, we know how far away they are from where we are trying to operate.

Lisa Garvin: And I guess people, to understand in the old days, you used to have to actually leave the OR, go to the MRI, and then bring the images back, correct?

Jeffrey S. Weinberg, MD, FACS: : Yes, that's a good question. What we typically do or at least in the last, I know 20 years or so, we've had the device that I like to term a GPS for the brain and we have that in regular Operating Rooms. It is not just in the BrainSUITE and that's based on a map, just as you have in your car GPS system, that is an MRI scan that we typically do before the surgery starts. And we have this GPS device that allows us to point to the brain, point to the tumor, and it allows us to figure out which is which and how to just take out tumor and not healthy brain. The problem is that as we are doing the surgery, the map that we have is based on the information we had the day before the surgery, not actually at the time of surgery. So, after you remove 50% of the tumor you are looking at a map that has 100% of the tumor and so, we like to have an updated map. So, the question that you asked was how do we used to do it, we would use this technology and we use ultrasound and we use our experience in taking out tumors to help us remove as much of the tumor as possible. But there are tumors that at the time of surgery look exactly like healthy brain. They might feel a little bit different but they look very similar. We know that there are structures which we want to preserve, we know that we don't want to injure those structures because they can lead to problems with speaking or moving or comprehension or seeing or other types of neurologic functions. So, any information that we can get that helps us preserve that is clearly beneficial. So, in regards to the way we used to do it, we've remove as much tumor as we could using the tools and techniques that we have and then typically get an MRI scan the following day, and then a small proportion of patients there would clearly be tumor left over and it's up to the clinician's decision to determine whether or not that amount warrants going back for surgery versus not and treating with other methods that are commonly standard of practice. And with this new device, we are able to get the MRI scan at time of surgery before even closing the patient's head and then getting our picture to give us an assessment of how the surgery is progressing.

Lisa Garvin: Now, before intraoperative MRI, were you having to do additional surgeries because of tumor left behind or were you going behind that with chemo or radiation?

Jeffrey S. Weinberg, MD, FACS: Well, clearly it depends on the type of tumor whether or not chemo or radiation is effective, but at least in our hands, the number of patients that went back for immediate surgery because of the amount of tumor that was left over was small. I don't know the exact numbers, but it's probably not--it's not zero, but we do have other methods for treating this disease. The one thing I will say though is that we know recently within the last five to ten years that the data is very conclusive that for all malignant brain tumors the amount of tumor--the patient does better based on the amount of tumor that's resected. So, the more tumor that we can remove in a safe fashion is best for the patient. And we know that that outcome is based on the amount of tumor that is removed and also means that the chemotherapy and the radiation works best when there is less disease remaining in the brain.

Lisa Garvin: So, do you feel like you're getting more of the tumor now with intraoperative MRI?

Jeffrey S. Weinberg, MD, FACS: There is no question. Our studies we have--our studies demonstrate that. We have a database that we keep prospectively as we are doing the surgery that shows we analyze why the surgeon is getting the MRI scan, how much tumor the surgeon thought that he or she removed, how much they think is left, and then actually looking at the MRI scan to determine whether or not we were right or wrong. And in fact, the MRI helps us in a large percentage of patients to remove enough disease that makes it worthwhile.

Lisa Garvin: Has there been enough data to show whether it's improved overall survivorship?

Jeffrey S. Weinberg, MD, FACS: Yeah, so that is a very important question because the tool in and of itself helps us remove more tumor. We already know that survival is based on the amount of tumor that's resected, so it's not that the MRI in and of itself improves survival, it's removing more tumor improves survival and this tool helps us remove more tumor. So, you just connect the dots and MRI remove more tumor, better survival.

Lisa Garvin: Who are the most likely candidates for this technique?

Jeffrey S. Weinberg, MD, FACS: It's really based on the surgeon and it is based on the type of tumor. There are certain tumors that based on their anatomy, their size, what we know they look like at the time of surgery that with very good confidence we can remove 100% of the part that we are going after. I use that term deliberately because frequently with malignant brain tumors, we can't remove every last cancer cell, but we can remove a certain amount of the tumor and we know that we can remove 100% of that amount without the MRI. There are those tumors that because of their size, their shape, their location, their grade, how we know they look at the time of surgery that will clearly benefit from the MRI and then there's surgeon preference. Some surgeons are very comfortable using the technology, other are not and it's really it's ultimately it falls upon the surgeon to make the decision to use the technology or not.

Lisa Garvin:: And from what I understand about glioblastoma multiforme which is probably the worst of the worst is that the tumor is really not encapsulated. It tends to send out little tentacle.

Jeffrey S. Weinberg, MD, FACS: Yes, so people come in and they base--they say the term tentacles or fingers, things like that, the thing that I tell my patients is that if you look at your hand or think of an octopus, you have the solid part of the tumor. The tentacles or the fingers look like a direct extension from the tumor. The problem is that the tumor cells that are left behind are not directly connected to the body or the palm of your hand. There is actually healthy brain tissue between the tumor and those invading cancer cells. And so, the best analogy I have been able to come up with is that you have a solid tumor which is the mass of either specifically in glioblastoma is a solid tumor or tumor and dead tissue which is the component of glioblastoma. And then in the periphery, if you have sprinkled on this table salt and from all the way up in the area you sprinkled ten flakes of pepper, those black flakes randomly distributed within the healthy brain are the cancer cells that are left behind. They are not directly connected to the main massive tumor, they are not accessible by surgery, they are not visible at the time of surgery, we unfortunately are not at the liberty to take an extra two inches of brain with the hope of getting clean margins. Number one, we can't get clean margins because we never know when that last pepper flake is in our specimen and not only that, that causes neurologic deficit. So, we remove the solid part and those pepper flakes, those tentacles or fingers, but the cancer cells that have the ability to walk through the healthy tissues are still left behind and those are the tumor cells that need to be treated with the chemotherapy and the radiation.

Lisa Garvin: So, it sounds like intraoperative MRI is really not the standard of care.

Jeffrey S. Weinberg, MD, FACS: Well, so we can never say it's standard of care. Number one, it is very expensive technology. So, to make a bold statement that says intraoperative MRI is the standard of care implies that any patient with a brain tumor has to go to one of the very limited number of centers that use it and use it in the appropriate fashion. However, it is still a tool that does help get as much tumor as possible. I think that the best thing is to choose a surgeon or surgeons or department where there is experienced handling the type of tumor that you have and then those people make use of the best tools that they have available.

Lisa Garvin:: Are there other surgical techniques that are kind of new crusting the wave of innovation as far as brain tumor surgery is concerned?

Jeffrey S. Weinberg, MD, FACS: So, there are--not, you are saying not related to intraoperative MRI?

Lisa Garvin: Correct.

Jeffrey S. Weinberg, MD, FACS: Well, outside of experimental chemotherapy, vaccines, drugs, viruses, things like that are being used. As far as surgery is concerned we have laser devices which are being used to heat tumors to the temperature at which point they are killed. There are drugs on the market now, not necessarily available in the U.S., but available certainly in Europe and being experimented within the U.S. that allow us to potentially see the tumor under fluorescent microscope during the surgery which help again in getting out more of the tumor. So, again tools which at this point help kill the tumor, but can't treat specifically with glioblastoma, those infiltrating tumor cells that are the ones that are responsible for the high malignancy of these diseases.

Lisa Garvin:: Have you been able to budge the survival rate at all, I mean, excluding glioblastoma multiforme, have you been able to up the survival rate in other malignant brain cancers?

Jeffrey S. Weinberg, MD, FACS: : Absolutely. So, when I started in 1993, the median survival was 12 to 14 months for patients with glioblastoma. In fact now, we are up at 18th month range and more importantly is that the tail of the survival curve, those number of patients living much longer is much greater. And so, I just saw a patient back who I operated on six years ago for glioblastoma and he is still alive. We have patients with low grade brain tumors who, median survival would have been five to seven years, that's now have ten years and it's not just surgery that's impacting, it's surgery plus it's the chemotherapy, it's the radiation, it's knowing how to mix the two to get the best possible outcome.

Lisa Garvin: What would be your message to patients who may have been diagnosed with brain tumor, what would you tell them in a nutshell?

Jeffrey S. Weinberg, MD, FACS: You need to find a team that knows how to take care of those tumors. I think that it's a very serious disease. It can cause significant problems and it's appropriate to find the right team for you that knows how to take care of patients with that disease and that includes a combination of surgery and chemotherapy and radiation, and just teams that treat them frequently is the place to go. And one last thing in regards to patients with brain tumor, we actually host every two years a brain tumor conference. This year it's occurring May 20th to 22nd and it's a great conference for patients with brain tumors and their families to come, discuss new treatments, old treatments, specific aspects and questions they have about their disease to interact on a more personal level with those of us who treat these diseases on a daily basis. It is really wonderful for caregivers. There is a large program for caregivers specifically without the patients. There are great support services. Everybody who will be there will be either physicians from the neurosurgery, neurooncology, radiation oncology, neuropsychology department, to the nurses that care for these patients, and it is really a wonderful experience. It is also for patients who were just diagnosed, who have never been seen by a physician we have consultation services available as well.

Lisa Garvin: Great. Thank you for being with us today. If you have questions about anything you've heard today on Cancer Newsline, contact askMDAnderson at 1-877-MDA-6789 or online at www.mdanderson.org/ask. Thank you for listening to this episode of Cancer Newsline. Tune in next week for the next podcast in our series.