JUDY WOODRUFF: Now, Senator Kennedy’s diagnosis and what is known about the treatment of brain tumors. Jeffrey Brown has more.
JEFFREY BROWN: Senator Kennedy has been hospitalized in Boston since he had a seizure Saturday. After a series of tests, his doctors at Massachusetts General Hospital issued a statement today, reading, in part, “Preliminary results from a biopsy of the brain identified the cause of the seizure as a malignant glioma in the left parietal lobe. The usual course of treatment includes combinations of various forms of radiation and chemotherapy.”
Malignant gliomas are diagnosed in about 9,000 Americans each year, making it the most common type of brain cancer among adults.
We learn more now from Dr. Susan Chang at the University of California-San Francisco Medical Center. She’s the director of the division of neural oncology.
Well, Dr. Chang, why don’t we start with a malignant glioma? What exactly does that mean?
DR. SUSAN CHANG, University of California, San Francisco Medical Center: Well, this tumor type is one that is a primary brain tumor, as opposed to other tumors where they can arise from other organs and spread to the brain.
The malignant glioma represents a tumor that is very infiltrative into the brain tissue itself and can be very difficult in terms of identifying the borders of the tumor from the normal tissue.
JEFFREY BROWN: And how does it cause seizures? And how dangerous is it?
DR. SUSAN CHANG: Well, it’s very dangerous in the sense that, depending on anywhere in the brain, the function of the brain is very specific to where the tumor may arise.
So, for example, if it’s in the parietal lobe, as it is in Senator Kennedy, we’d expect that some of the symptoms may be related to difficulty with coordination or sensation. The seizure effect is because of irritation of the brain within a normal tissue, causing electrical abnormalities which result in a seizure.
JEFFREY BROWN: But go back, tell us a little bit more about the location, the left parietal lobe. What exactly happens in the brain there? And what would be the significance of that particular location?
DR. SUSAN CHANG: So in the left parietal lobe, normally we think about — which is the dominant part of the brain in patients who are right-handed and even in most patients who are left-handed, the dominant side of the brain is on the left side, which means this is where the function for speech and language lay.
In the case for Senator Kennedy, without looking at his MRI scans to really look at the location, specifically in the parietal lobe, the concerns would be whether, as a result of the tumor, he can have symptoms related to abnormal sensation or abnormal coordination, not knowing where his arm or leg may be in space and being able to coordinate.
Factors impacting possible surgery
JEFFREY BROWN: Now, doctors said the treatment would be decided after more tests. What exactly will they be testing for? And what options are there?
DR. SUSAN CHANG: So the term "malignant glioma" refers to various types of tumors that can arise in the brain itself from the supporting cells around the neurons.
And so what they're going to be looking at is specifically what type of cell makes up the tumor and also what grade of the tumor it is. There may be some cytogenetic and biological characteristics that are going to be investigated within the tumor itself, as well.
JEFFREY BROWN: Senator Kennedy is 76. Would age be a factor in deciding whether to go ahead with surgery?
DR. SUSAN CHANG: The decision about surgery is really made based on where it is in the brain and the extent of involvement in the normal tissue. So one of the characteristics of malignant glioma, unfortunately, is that it is very infiltrative and invasive into the normal tissue.
So a surgical resection has to be taken very -- or surgery itself has to be taken very seriously, in terms of what effect it may have on the normal brain.
JEFFREY BROWN: Well, tell us more about the various treatment. In the statement that I read, they referred to combinations of various forms of radiation and chemotherapy. Now, is that after a possible surgery or in addition to?
DR. SUSAN CHANG: So usually after -- if surgery is going to be performed to try to remove more of the tumor, then follow-up treatment would include radiation and chemotherapy.
JEFFREY BROWN: And how long would those last?
DR. SUSAN CHANG: The radiation treatment usually lasts for six weeks at a time. It's a daily treatment, Monday to Friday, every day for approximately six weeks, various doses. And the chemotherapy, depending on the type of tumor that they finally diagnose him at, may consist of chemotherapy pills that can be given in conjunction with the radiation.
JEFFREY BROWN: And then, when you try to look to a particular prognosis, what are the key factors?
DR. SUSAN CHANG: So there are patient factors that are important to consider, one being age. The same type of tumor within a young patient, those patients may do better than a patient who is older. So age, by far, is very important, in terms of how patients do.
The performance status we call it, or how well a patient is, are they independent? Are they active? Those patients also fare better than patients who may be more symptomatic from the tumor or have other symptoms.
In addition, malignant glioma spans two different grades, grade three and grade four, and that makes a difference in terms of outcome. So those are the tumor factors, in terms of whether it's a more aggressive, which is the most aggressive is grade four.
And so those are the major factors that we would be looking at, in terms of the results of the pathology that will be finalized.
JEFFREY BROWN: Is it possible to say anything in general about life expectancy?
DR. SUSAN CHANG: In general, malignant glioma is very aggressive, especially at the grade four level. It's the most aggressive tumor that there is.
For a grade four tumor, the same name is called a glioblastoma. For that type of tumor, the average survival is approximately a year to longer. It depends on the patient factors.
JEFFREY BROWN: And, finally, how dynamic an area of research is this? Have we seen many changes in the past years? Where is the science here?
DR. SUSAN CHANG: Well, I think that's an excellent question, because I think to understand the biology of the tumor is what is going to give us insight into how we can better treat these tumors.
We are doing a lot of research, in terms of the epidemiology, in other words, what are the risk factors for developing these tumors? We still don't understand all of the factors that may relate to the causation of these tumors.
We're trying to understand where they come from. Is it from stem cells in the brain tissue?
We're also looking at various signaling pathways and abnormalities in the tumor that we can target using various approaches.
So I think a very generalized or multidisciplinary approach to the treatment of these tumors is the key. And through a lot of the research that's ongoing, that is where we're going to find the answers.
JEFFREY BROWN: All right, Dr. Susan Chang, thank you very much.DR. SUSAN CHANG: You're very welcome, Jeff. Thank you.