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  © 2008
  University of Idaho
  All rights reserved.
  Psychology Dept.
  University of Idaho
  Design - P&D  CTI

First of all as we can see in slide two, there are more than 120 different types of brain tumors.  They can occur in any part of the brain or the spinal cord.  Of individuals who develop a brain tumor, only 31% survive 5 years after the diagnosis, so it’s a pretty serious problem.  The treatment for brain tumors often requires treating the entire brain rather than just some particular part of the brain.  We’ll talk about that a little bit more later and why it’s important. 

As we see in slide three, the brain contains both neurons and glial cells.  It’s also covered by the meninges, contains blood vessels, and also contains a wide variety of different cavities.  In any of these places a brain tumor may develop. 

Tumors (as we see in slide four), are classified in a variety of ways.  But, in general, they’re classified according to the type of cell which causes the tumor.  The tumors can be fast growing or slow growing, and the tumor types you see in adults are often different than children’s tumors.  Tumors can also arise from other places beside the brain and then move to the brain and cause problems.  As we see in slide five, tumors that begin in the brain are called primary tumors and involve many different types of tumor cells.  As a consequence, they are very, very difficult to kill.  So, what you have is a tumor containing a variety of different sites and different cell types.  Thus, each cell type is different and resistant to different types of drugs that we have.  Consequently a drug that might work on one cell type will not work on another cell type.  There are also a wide variety of different types of primary tumors and I’ve listed a few here (on slide 5) e.g., astrocytoma. 

Most tumors, as we see in slide six, basically come from astrocytes.  When a cell comes from a particular type of glial cell, this is what we call a glioma.  Again, there’s a variety of different types of which I’ve listed here.  Tumors can also develop in the meninges.  When this occurs it is called a meningioma.  Finally, we also have tumors and nerves at the base of the brain.  Often these come from Schwann cells and are called acoustic neuromas or Schwannomas.  Again different types of cells cause different types of tumors. 

 Well in addition to primary tumors, we also have a wide variety of tumors that come from outside of the brain.  These are called secondary tumors and are related to what we call metastatic brain tumors.  Metastatic brain tumors are cells that come from other areas of the body.  These include the liver, the breast, and the lungs.  These tumors will resemble cells where the tumor actually begins.

Now, there are lots of different types of symptoms for brain tumors.  As we can see in slide 10, the symptoms are going to depend on where the tumor is located.  For example, in the frontal lobe you might get weakness and confusion.  In the temporal lobe, you might have seizures or specific types of aphasias, occipital lobes visual problems, and the parietal lobe sensation problems.  So, again, it depends on where they begin and what the kind of damage they cause.

Now, as these tumors get enlarged, the more and more tissue becomes destroyed.  In addition, the tumors can infiltrate between the different types of neural tissue.  This makes it much harder to remove when you’re trying to get rid of it. 

Finally, there are other issues that are involved with tumors and treatment for tumors.  That is, some tumors live in very low oxygen environments.  Thus they are very radioactive resistant and they're far away from blood supplies.  When that occurs, it decreases the probability for successful treatment. 

So what are some treatments for brain tumors?  Well as we can see in slide 13, there are many, many different types of treatment.  In general, there are over 400 different protocols as of this time.  What we usually see as the standard treatment is a combination of three things; surgery, radiotherapy and chemotherapy.  There’s also a wide variety of other procedures that one can use and I’ve listed some of these in slide 14.  They include radiosurgery, the gamma knife, the x-knife, lasers and a wide variety of other techniques.  In general, these just help you to refine the procedures that are related to removal of the particular material.

There’s a major treatment problem/issue for physicians.  So, I want to kind of walk you through this issue, and show you why you need to use a combination of the three procedures.  Let’s imagine that we have a gram of a brain tumor and this gram contains one billion cells.  So, we have a brain tumor we’ve identified, and the physician says let’s go in and cut it out.  Let’s say that you get 99% of the brain tumor (you can use all sorts of different techniques to help such as ultrasonic aspiration, computer assisted stereotaxic surgery and many, many other types).  But, regardless of the best technique that you do, you still have 1% left.  So, with that 1% we still have 10 million cells remaining in the brain.  So, we have to use some other techniques.  Let’s say the next technique that we use is radiation.  So, if the radiation again is 99% effective, we still have 100 thousand cells left.  As a consequence of that, those cells can grow if we stop there.  So let’s again use another technique in combination with that.  Let’s say that we use chemotherapy in the site.  So, if this again is 99% effective, we still have remaining 1000 cells.  So, even when we have the best techniques, if we’re not able to get all of the cells, (note that we still have a bunch remaining) they can again cause tumors.  Another problem is that rarely do you get a 99% removal rate, and of course, that is going to contribute to survival rates down the road over the long term. 

In addition to that, cells often grow in multiple locations.  So, as we see in slide 17, what you need to do if you're going to be successful, or at least mostly successful is you have to treat the entire brain.  As we see in slide 18, newer models just do that.  In essence what they’re going to do is the surgery first (depending upon the particular type of tumor that one has), then we’re going to radiotherapy of the whole brain, then chemotherapy of the whole brain.  You may need to use multiple substances to help with chemotherapy, and you may need other substances to help the molecules related to the chemotherapy move across the blood brain barrier.  Finally, and the way of the future, is what we call immunotherapy.  Basically, we’re going to use the immune system to target specific types of tumor cells.  This is on its way now and hopefully will be used more in the future.

So in conclusion, there’s lots and lots of different techniques and different work that’s being done to help with brain tumors.  In addition, the success rate is much better than it was even 10 years ago.  As we continue to develop better techniques, better technology, and better drugs, we will only be able to see a reduction in brain tumors, and better treatment prognosis in the long term. 

In our next section we continue on with this discussion of disorders, so until then we hope that you’re enjoying the class and you’re having a great day.