Dr. Vogelbaum: That’s a tough number to come up with. Personally I probably treat somewhere between a hundred and fifty to two hundred patients with brain tumors each year.
What’s the hardest part about treating someone with a brain tumor?
Dr. Vogelbaum: For the types of brain tumors that I treat, which are mostly the malignant brain tumors, the hardest thing is that we don’t have a cure for the vast majority of them. The treatments we use we know help and they help to extend life, and if they’re used well, they help to maintain quality of life, but they’re not cures and we haven’t found a cure for most of the malignant brain tumors yet.
If I understand correctly it’s also very difficult, because if you don’t get all the cells out from the brain tumors they can grow back pretty quickly?
Dr. Vogelbaum: Well the truth in surgery for malignant brain tumors is that we can never get all of the tumor cells out. We take out the worst part of the tumor – we take out the part that is taking up space – that is pushing on normal functioning parts of the brain and creating pressure inside the head, which can be dangerous. We know if we can take out the highest grade tumors, if we can take out everything that lights up with contrast, we have good reason to believe that patients will live longer as a consequence of that. So that’s one of the major goals of the surgery. However, we’re not curing the disease with surgery alone. There is a microscopic infiltrative portion of the tumor that goes inches away from where we do our surgery; we know there are tumor cells out there.
Are these the types of tumors that almost look like they have fingers that grow through the brain?
Dr. Vogelbaum: That is one of the terms that’s used to describe infiltration. It’s really that the tumor cells are infiltrating within the brain matrix itself and coexisting with normally functioning brain until they grow to be a number where they start to impair function.
How do you see these types of brain tumors affect your patients?
Dr. Vogelbaum: Patients come to us with a variety of symptoms that had led to the imaging that showed that they had a brain tumor. One of the more common symptoms is a seizure out of the blue in an adult. Adults don’t develop seizures out of the blue for too many reasons. Sometimes people will have headaches that are different from the ones they normally have and that are progressively worsening. Sometimes they’ll present with new weakness or problems with their speech or language; sometimes the symptoms seem like a stroke, but actually strokes are far more common than brain tumors, but that can be one of the symptoms of having a brain tumor. So there’s a variety of symptoms.
Traditionally how would you image the brain to see where the tumor is?
Dr. Vogelbaum: Years ago one of the great developments in this field was the use of CT scanning. That became a very important tool for seeing exactly where a tumor was located. Since then MRI has become available and it’s a much, much better tool for actually showing us the intricate detail that we need to see in order to understand what’s going on and to plan a surgery and to plan all of the treatment.
What’s the down side to MRI?
Dr. Vogelbaum: There really isn’t a downside to MRI. Some patients don’t enjoy going through an MRI because they have to be inside a fairly tight tube and it is a noisy environment for the scan, but that’s really the only downside to it.
Could it give you all the details you would need?
Dr. Vogelbaum: It gives us the details we need. In fact it is by far the best tool. There are a few times when we have to work with CT scan only and it’s really turning back the hands of time when we’re doing that.
But now you’re adding something to the MRI’s.
Dr. Vogelbaum: It’s not really adding to the MRI. It’s actually a separate imaging approach and it’s not diagnostic; it’s purely within the OR and during surgery.
You use the MRI scan as your road map for the surgery; then you get in to the surgery; how do know you’re getting everything?
Dr. Vogelbaum: For many decades before we had MRI, and even when in the initial years when we had MRI, the surgery was done based upon the surgeon’s understanding of anatomy and the ability to interpret the MRI and apply it to the patient in three dimensions, which is what we are train to do, but the truth is we didn’t have much to guide us. We made very large openings in the skull and then we had to try to figure out where the tumor was in real time. Of course the danger there is one could end up going in to the wrong part of the brain. So along came a new technology which was called Image Guided Navigation.
How did this new technology help?
Dr. Vogelbaum: It allowed us to use a preoperative MRI and register it with the patient when they were asleep in the OR. In other words, we could load the MRI in to a computer system that we had in the OR and show that system what the patient’s head position was; that allowed us to navigate using special tools, very similar to the way that one uses navigation in the car. It shows us where we are. And we could plan our surgeries that way and make smaller openings, go directly to the tumor; making it safer and a more effective operation.
Do you ever come across any problems during operation?
Dr. Vogelbaum: The problem is that during the operation the brain shifts, especially when there’s a large tumor, removing a lot of it; the brain shifts and we lose that registration. So one of the next innovations was the development of intraoperative imaging; starting with ultrasound and then CAT scans and finally MRI. That’s a great way to be able to do the surgery, obtain a new set of images while we’re there in the OR and then continue with an updated map. The problem is that’s a very expensive solution and also it interrupts the flow of surgery because we have to stop, cover everything and then perform the imaging. Each time we do that it can actually lengthen the operation by an hour, which is not such a great thing.
How many times would you stop a surgery?
Dr. Vogelbaum: I try to do it with just one image set. One additional image set but sometimes it can be two, three, or even four. So that can add a lot of time to a surgery. The newest innovation is the use of a fluorphor that is a substance that glows indicating where tumor cells are present and the substance is called 5-ALA or 5-aminolevulinic acid. This is a substance that is used therapeutically for certain types of skin cancer. It’s used in a process called photodynamic therapy. The 5-ALA is converted by enzymes that are normally present in cells into another substance which glows; it glows red when it’s exposed to blue light. Usually that’s used as a topical application and that’s the way it’s approved in the US. In the case of using it as a way to find tumor cells, it’s actually mixed in water and then ingested before surgery.