M. D. Anderson Cancer Center
Cancer Newsline Audio Podcast Series
Date: November 17, 2008
Duration: 0 / 11:44
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Welcome to Cancer Newsline a weekly podcast series from The University of Texas M. D. Anderson Cancer Center. The aim of Cancer Newsline is to help you stay current with the news on cancer research, and the rapidly changing advances in cancer diagnosis, treatment and prevention and provide you with the latest information on reducing your family’s risk of being diagnosed with cancer. I am your host Doctor Leonard Zwelling. Today we will be talking with Dr. Eric L. Chang, associate professor of Radiation Oncology about the undocumented affects of brain metastasis and brain irradiation and new ways to administer radiation which will have lower side effects. So let’s talk about the obvious question. How frequent is brain metastasis and which cancer spreads from other parts of the body to the brain
The answer to the first question is that brain metastasis are very common unfortunately. There are approximately 170,000 new cases of brain metastasis each year in the United States and primary cancers that frequently metastasis include patients with lung cancer, breast cancer renal cell cancer, melanoma, and colorectal cancers among others.
So they’re the common cancers?
Those are the common cancers.
Tell me why do you think this has become a problem now? Is it because out primary therapy for the cancers has become so much better and the people are living longer giving the metastasis a longer time to generate?
I think that’s part of it. The more affective systemic agents is allowing patients to live longer and perhaps develop more metastasis disease.
So tell us about specifically study you did, why you did it and what the results were?
So this is a randomized study that was designed to compare two currently practiced standard of care strategies for patients new diagnosed with 1 to 3 brain metastasis and those two strategies are number one to manage patients with radio surgery alone and the other strategy is to manage patients with radio surgery plus whole radiation therapy given right after radio surgery.
Tell us what radio surgery is?
Radio surgery is a non-invasive way of delivering a very high dose of radiation precisely to the tumor itself while sparing the remainder of the brain from significant amount of radiation.
So there is no real surgery involved in terms of scalpels?
That’s correct. The term radio surgery is used to denote the fact that the procedure is given in a single day single session.
So it’s a single session like usual radio therapy which goes over weeks?
So do you identify the site of these metastasis with imaging studies? Is that how it’s found?
Yes. In this study all patients were diagnosed with their brain metastasis using a brain MRI within one month of their enrollment.
So what were there results of your study cause one would think more radiation you give the better off the patient would be?
That’s correct, that is one point of view. One point of view holds that ah…those patients receiving the whole brain radiation therapy would have the best tumor control of there brain metastasis and therefore should be free from neurologic sequelae compared to there counter parts who didn’t brain radiation therapy and what we found was that in the patients who received the brain radiation therapy in conjunction with brain surgery the incidents or risk of developing neurocognitive decline was 49% verses 23% in patients who received radio surgery alone.
That’s a big difference. What kind of ways were you able to measure neurocognitive decline?
The way we measure the neurocognitive decline was specifically with a test called the Hopkins verbal learning test revised. This utilized a number of words the patients were asked to recall these words right after they were told by the person administering the test.
So the idea was…had you have hints that this might be the case of prior work with whole brain radiation that patients were showing an increase amount of neurocognitive dysfunction?
I had absolutely no idea. I felt the trail could go either way. I felt that patients in vulnerable populations such as very young, children, and elderly patients might be susceptible to the risk of developing some sort of neurocognitive changes or decline with brain radiation therapy but I didn’t have any idea it would be this dramatic.
Did it have any affect on survival and all did one group survive better then another group?
Um…that’s an excellent question and we were very surprise to find that there was indeed a survival difference between the two arms even though it was not something we were not looking for the original design.
Which arm did better?
The patients who received the radio surgery alone had a higher survival rate compared to patients who had radio surgery plus whole brain radiation.
This is one of those examples where more may not be better.
So will this affect the treatment of primary brain cancer at all will people try radio surgery following real surgery and see whether or not that will have an affect on people with primary brain cancer.
I don’t think this extend to patients with primary brain tumors because the biology is so different and I assume your referring to the primary gliomas this really doesn’t extend or extrapolate to those patients it really just applies t patients with limited metastasis brain disease.
Umm…do you think this now will become the standard of care throughout the country. The use of whole brain radiation therapy with cancers that spread to other parts of the body to the brain will actually go away pretty much.
In my mind at least in my practice I believe that this will change how I would currently manage patients with brain metastasis and using radio surgery in combination with whole brain radio surgery therapy. I think it has the potential to change the standard of care in the United States although I should qualify by this is highly contentious issue being actively debated right as we speak. Umm…as you know it’s very hard to convince people who already believe what they want to believe so we’ll just have to wait and see.
But in this particular case the difference in the two groups were so great that the group that monitors the data coming out of your trial. Double blinded? Could not be double blinded.
It was randomized the data monitoring board we needed to stop because the amount of complications was so high in the brain radiation group.
Yes that’s correct. The data monitoring committee um…essentially halted this trial early on cause the trail met the stopping rules and basically said that we should not continue anymore because there was a difference in which they felt that they had 96% confidence that one arm was doing worst then the other arm.
You accrued 58 patients. How many did you think you needed to get the answer?
We were aiming to accrue 90 patients.
So you were just barley over the half way mark when this obvious difference occurred.
Yes. That’s correct because um…very strong biases. What is the best way to treat patients? Amongst patients, and there caregivers many patients who present to our clinic have a pre conceived notion on how they want to be treated already and don’t wish to be randomized so there in lies the difficulty in doing the study.
It also shows how important it is to have an independent monitoring group that looks as the data is coming out so that even if the physician so even if there were double blinded test and you didn’t know which therapy your patients were getting. Someone does and constantly looks at this to access the efficacy and safety.
I completely agree
Will there be an opportunity to use radio surgery in other forms of cancer besides brain cancer?
Ah…Yes! So a…emerging field right now termed the stereotactic body radiation therapy and this is a term used to describe what we do in the brain to extracranial sites outside the brain. So sites outside the brain such as the lung, the prostate, the pancreas, the liver, the kidney and so this is a emerging field that is gaining popularity to try to use some of the benefits that we see treating patients brain radio surgery extend those benefits to patients with disease in other sites of the body.
Now the neurocognitive analysis has been always looked at in children who got some sort of radiation therapy that was a concern. Is this something that going to be done more and more in adults as well to make certain the therapies we employ don’t do more harm then good.
Um…I think there is a push to do that we’re are very fortunate at M. D. Anderson we have a team lead by Dr. Christina Meyers who runs this program to make the particular evaluations and assessments available to us. I don’t know if other centers have this type of luxury. I think this certainly highlights the need to be able to do these types of tests because neurocognition is so important in terms of the daily functioning of these patients life.
And it definitely gives substance to our treatment of whole patients where concerned about the holistic approach with people with cancer and their life style. Thank you Dr. Chang. Listeners if you have any questions about anything you heard today on Cancer Newsline. Please contact M. D. Anderson at 1-877-MDA-6789 or online www.mdanderson.org/ask.. Again this is a weekly series please tune in again next week for our next episode of Cancer Newsline.
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