MD Anderson Cancer Center
Lisa Garvin: Welcome to Cancer News Line a podcast series from the University of Texas, MD Anderson Cancer Center. Cancer News Line 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 and today our guest is Dr. John DeGroot he is an associate professor of neurooncology here at MD Anderson and we're going to talk about kind of a broad subject but we'll try to narrow it down a little bit for our audience, central nervous system tumors. Welcome Dr. DeGroot thanks for coming and being with us today.
Dr. John DeGroot: Thank you for having me.
Lisa Garvin: Let's start by talking about what exactly the central nervous system is.
Dr. John DeGroot: The central nervous system encompasses the brain, the spinal cord and typically people also include spinal fluid which is...coats the brain and spinal column.
Lisa Garvin: What exactly when we talk about the central nervous system what sort of functions does this system control?
Dr. John DeGroot: The central nervous system controls a wide variety of things including very basic functions such as the level of consciousness all the way to actually our knowledge, our ability to understand words, our ability to speak words, to control muscle movement throughout the body and it also perceives sensation.
Lisa Garvin: So a tumor in a particular place could really have a serious effect on any one of these functions.
Dr. John DeGroot: That's correct the symptoms of presentation are really dictated by where the tumor arises in the brain.
Lisa Garvin: When we talk about central nervous system tumors as a family there are quite a few subtypes of these tumors, correct?
Dr. John DeGroot: Correct there are over 40 different subtypes of primary brain tumors and these are tumors that arise from structures within the brain and that's going to be differentiated from metastatic tumors which would be arising from a solid tumor or a hematologic tumor that then travel to the brain.
Lisa Garvin: And as far as central nervous system tumors not all of them are malignant, a fair amount of these types are benign, are they not?
Dr. John DeGroot: That's correct so these we typically use a grading system, grade 1 through grade 4 and grade 1 tumors many time are surgically curable.
Lisa Garvin: Now in children this is a fairly common tumor is it not?
Dr. John DeGroot: Right so it's probably the second most common type of tumor in the pediatric population.
Lisa Garvin: In adults it's a little less frequent?
Dr. John DeGroot: Right so in adults primary brain tumors only account for maybe 2 ½ percent of all tumors that occur in the body.
Lisa Garvin: And do you have a particular focus in your work; do you focus on particular types of CNS tumors in your clinical work?
Dr. John DeGroot: Our focus here in the brain and spine center at MD Anderson is mainly focused on the most aggressive types of primary brain tumors; these are typically grade 3 and grade 4 tumors. They also tend to be the most common in terms of presentation and aggressiveness.
Lisa Garvin: Can you name some of those most common types that you see here in your practice?
Dr. John DeGroot: Sure the most common one is glioblastoma which is a grade 4 primary brain tumor and second behind that would be grade 3 which are anaplastic tumors.
Lisa Garvin: Typically treatment for these tumors is surgical in approach or at least that's the front line approach.
Dr. John DeGroot: Correct surgery is critically important for a couple of reasons; one is that it is essential for obtaining the diagnosis. The second is that many times patients might have symptoms related to compression of normal brain structures and so removing the tumor can actually improve symptoms. And the third is that for many types of tumors the more tumor that can be resected safely the better the prognosis.
Lisa Garvin: Now is there...is it often joined with radiation or chemotherapy either before or after surgery?
Dr. John DeGroot: For the malignant brain tumors for grade 3's and grade 4 there is...it is necessary to continue treatment following surgery with either combinations of radiation together with chemotherapy or just radiation alone.
Lisa Garvin: And this is to try to get any microscopic disease that may be left or...
Dr. John DeGroot: That's correct so grade 2, 3 and 4 astrocytomas are not surgically curable and so despite aggressive surgical intervention there are still microscopic cells that are left within a 2 to 3 cm margin of the resection cavity. So any treatment given after that is actually directed towards those residual tumors.
Lisa Garvin: I know that the prognosis typically for glioblastoma multiform is pretty low but do survival rates kind of span the spectrum depending on the type of tumor?
Dr. John DeGroot: Yeah so there's multiple prognostic factors that are important including patient's age, the grade of the tumor, the extent of resection and also the patient's performance, how well they're able to carry out activities of daily living and take care of themselves and business. So the spectrum can range from without treatment you know survival of a couple of months all the way to many years.
Lisa Garvin: Is the treatment approach different for benign tumors?
Dr. John DeGroot: So for grade 1 tumors, which there are many different varieties they can be surgically cured, so if a surgeon is able to resect the tumor the patient would require no additional treatment after that. However there are some tumors where intervention isn't necessary and the patient can just be followed with serial imaging over long periods of time. Many times without need for intervention.
Lisa Garvin: So this would be maybe a small benign tumor that's not affecting critical structures?
Dr. John DeGroot: Correct.
Lisa Garvin: And how many tumors do you see along the spinal cord, we've talked about kind of the brain and the skull cavity how many tumors do we see in the spinal cord or in the spinal cord fluid?
Dr. John DeGroot: So tumors in the spine are much less common but the same types of tumors can occur in the spine so grade 3, grade 4 astrocytomas can occur in the spinal column itself just less commonly.
Lisa Garvin: And you said that sometimes the fluid can be affected as well.
Dr. John DeGroot: So primary brain tumors can spread into the spinal fluid although it's very rare, however when you talk about systemic cancer such as breast cancer, lung cancer, melanoma those tumors can spread secondarily into the spinal fluid.
Lisa Garvin: Is there a common group of symptoms for central nervous system tumors that people might be aware of?
Dr. John DeGroot: The most common symptoms for primary brain tumors are things like headache, patients have seizures and then really beyond that it really depends on the location of the tumor. There are some certainly more subtle changes such as memory loss or behavioral changes, changes in personality or if it occurs in parts of the brain that controls language somebody might have difficulty understanding or being able to speak or they may have weakness or numbness.
Lisa Garvin: Do you often catch these tumors at an early stage?
Dr. John DeGroot: It's very difficult to catch them at an early stage unless a patient has a presenting symptom. Occasionally somebody might have been in a car accident or had an MRI scan for a different reason and then incidentally found to have one of these types of tumors.
Lisa Garvin: What sort of treatments...are there targeted therapies or new forms of minimally invasive surgery or radiation that are being studied to kind of help treat these tumors without effecting nearby structures?
Dr. John DeGroot: So the standard of care for glioblastoma remains surgery followed by the combination of radiation and oral chemotherapy called temozolomide and then followed with adjutant temozolomide. There are a lot of clinical trials and a lot of research ongoing to identify drugs that are targeting very specific molecular pathways but at this time we don't have any of those drugs that are actually approved for the treatment of glioblastoma.
Lisa Garvin: And we had talked a little bit before the podcast about proton therapy; I do know that our proton therapy center here at MD Anderson does a fair amount of treatment of central nervous system tumors particularly in children, what would the advantage be to proton therapy?
Dr. John DeGroot: We believe that proton therapy causes less injury to surrounding structures and so we actually have ongoing clinical trials to evaluate whether or not that's the case and in particular whether or not proton therapy for malignant brain tumors is able to preserve cognitive function.
Lisa Garvin: So Dr. DeGroot do you have like final words of advice that you can give to people may have been diagnosed with a tumor or may suspect that they have one?
Dr. John DeGroot: I think one of the most important things is for people not to lose hope, I think people should seek out a second opinion at a center of excellence where I think the care for these types of brain tumors has really been optimized. We have a lot of clinical trials that are ongoing that offer new and exciting treatments for these types of tumors.
Lisa Garvin: Great thank you very much. If you have questions about anything you've heard today on Cancer News Line contact, Ask MD Anderson at 1 877 MDA-6789 or online at mdanderson dot org slash ask. Thank you for listening to this episode of Cancer News Line, tune in for the next podcast in our series.