List of Most Common Terms
To be diagnosed with GBM is to enter a bewildering maze of terms that are hard to pronounce and spell and even harder to remember. Here is a quick and handy lay reference from our group members, terms we scratched our heads over when we first started our GBM journey.
- Avastin: The other chemotherapy drug known to work well for GBM, at least for a while. Avastin, also known as bevacizumab, is usually given by IV infusion every two weeks. It works by stopping the tumor from making new blood vessels. Usually it is used after a patient has recurrence on temozolamide, but there are various studies and protocols now where a newly diagnosed patient takes the two drugs together. Side effects include tiredness and possible stomach ulcers, strokes, or blood clots.
- Clinical trial: The process by which new medicines are developed and tested on patients for safety and to make sure they actually work. Clinical trials are important for GBM patients, because there are really only a couple of medicines for GBM and more are desperately needed. Many times the only way to get a new medicine is to participate in a clinical trial. You can search for clinical trials near you on www.clinicaltrials.gov . Many times a trial is "blinded," which means neither the patient or the clinician giving the medicine knows whether it actually is the medicine or a placebo. This is often done because the psychological factor of thinking you are receiving a lifesaving medicine can actually cause you to do better in the trial than you would do otherwise, and skew the results. The group that doesn't actually receive the medication is known as the "control" group. Most trials use a control group to see if the medicine actually does produce a different outcome compared to others who were treated the same except for not getting the test medicine.
- EGFR: Epidermal growth resistance factor. A protein that sits on the outside of many types of cells. In GBM, lung cancer, and prostate cancer, mutant forms of this protein are found, and more of the protein than normal cells have. When this protein is activated it causes many things we don't want, such as cells that don't die of old age when they're supposed to, cells that grow and divide out of control, and new blood vessels to form that feed the tumor. A common variant GBMs are tested for is "EGFRvIII." Understandably, many clinical trials have started to evaluate medicines that are supposed to stop this protein. So far, none of them have done very well. Your tumor may be tested for this to see if you might be eligible for a clinical trial.
- Blood Brain Barrier (affectionately known as the "BBB"): We all know that blood carries oxygen and nutrients to all our body cells, while picking up waste products and delivering them to the lungs, so carbon dioxide can be blown off, and the liver and kidneys, so other waste materials can be disposed of. The very tiniest blood vessels we have throughout our bodies are called capillaries. In the brain, the capillaries are specially designed so that a lot of things in the bloodstream that can get into all our body tissues, such as bacteria and large molecules, cannot enter the brain tissue. Collectively this is known as the blood brain barrier, and it poses a problem in brain cancer since a lot of cancer drugs cannot pass through it. This is one of the reasons GBM is so hard to treat and why we need new drugs for it.
- Decadron, AKA dexamethasone: A brain tumor causes serious swelling of the brain. Since the skull can't expand, the pressure causes headaches and a lot of other nasty symptoms such as vomiting and confusion. To take down all this swelling, especially when a surgeon is likely to be in there causing yet more trauma, most brain tumor patients end up taking this medicine. It is a powerful steroid and helps many of the symptoms of a brain tumor. Unfortunately, large doses of any steroid tend to cause bloating, water retention, a paranoid or irritable personality, thirst, excessive hunger, weight gain, muscle loss--especially in the large thigh muscles--and can even cause diabetes. Elsewhere on the site is a short article, "If you're taking Decadron read this!" Read it.
- Enhancement: An MRI is not an X-ray. Rather than passing X-rays through the brain to produce an image, an MRI uses a rather complicated system of magnets to display areas where hydrogen atoms are as white. Fewer hydrogen atoms read as black on an MRI. Where the brain swells or tumor is inducing more blood vessels to be made, there is more fluid, more water, and more hydrogen, thus an area that looks white on the MRI picture. "Enhancement" is the term for this. Lots of things can cause enhancement; it isn't necessarily tumor.
- General practitioner: Your good old family doctor. Even though you are in treatment for brain cancer, if you get gout or diabetes or something else unrelated to your cancer, like a case of the flu, you will still see this doctor for these other ailments. Be sure he or she knows all the meds you are taking, and before you go check with your neuro oncologist so you will know whether or not he/she will permit you to have shingles vaccines or flu vaccine before your general practitioner tells you that you need them.
- Glioblastoma or "GBM": GBM, also known as a grade four astrocytoma or glioblastoma multiforme, is the worst and most aggressive grade of the astrocytomas. Astrocytomas are brain tumors that arise from astrocytes, the star-shaped cells that support and feed nutrients to the neurons. Astrocytomas come in grades one through four, with one being very slow-growing and four being very the fast-growing and aggressive "GBM". The grades also refer to the degree to which the cells in the tumor exhibit difference from normal astrocytes.
Sad to say, GBM overall has a very poor and short prognosis. It's right up there with pancreatic cancer as being one of those cancers we just don't have the greatest of treatments for yet. But, we have to use the word "overall" because there is a great deal of variability in how individual patients do. In our support group of almost 1500 members, we have heard of those patients who have survived with minimal deficits for over ten years; those who are living with mild to moderate deficits two to five years past diagnosis; and those who succumb to their disease within fourteen to eighteen months. And then there are those whose disease is very rapidly progressive, or who were not candidates for surgery or chemo for some reason, who only survive three to eight months past diagnosis.
All these people get averaged together to get that fourteen month median survival figure you will see quoted wherever you go to look this up. Does it say a lot about how you yourself (or your loved one) will do? Not necessarily. Any of us will tell you, we are not a statistic, and neither are you!
- Hospitalist: A medical doctor who works only in a hospital to treat problems that crop with patients while in the hospital. If you are diagnosed with GBM and then, for example, you also have diabetes, the hospitalist is the person who stops by, reviews your chart, and issues directions for the nurses to give you insulin while you are in the hospital. After you leave, you don't see this doctor again. (We hope.)
- MGMT: A gene you hope is "methylated" in your tumor. Its full name is O-6-methylguanine-DNA methyltransferase (say that one three times fast). This gene helps a brain tumor repair DNA damage caused by chemotherapy. Generally tumor types where this gene is "methylated" respond better to the chemotherapy of choice for GBM, temozolamide. Usually your tumor will be tested for the presence of this gene. Nothing is carved in stone, however, and among our group members there are many stories of people whose MGMT was more unmethylated who responded well to temozolamide anyway.
- Midline shift: When taking MRI's to chart the behavior of GBM, sometimes a tumor is noted on one side of the brain that is so large or generates so much pressure that the dividing line between the two halves of the brain looks pushed to one side, hence the term, "midline shift."
- MRI: Stands for "magnetic resonance imaging." The standard test performed usually every two months to check on tumor progress and see if chemo and radiation are working. An MRI is not an X-ray. Rather than passing X-rays through the brain to produce an image, an MRI uses a rather complicated system of magnets to display areas where hydrogen atoms are as white. Fewer hydrogen atoms read as black on an MRI. Where the brain swells or tumor is inducing more blood vessels to be made, there is more fluid, more water, and more hydrogen, thus an area that looks white on the MRI picture.
- Neuro oncologist: A medical doctor specializing in the use of chemotherapy for tumors of the brain, nerves, and spinal cord. This doctor will supervise any chemotherapy you will be taking. Most people see their neuro oncologist about once a month, and meet him or her when ready to start radiation and chemotherapy.
- Neurologist: A medical doctor specializing in diseases of the nervous system. Those of us with mild, odd, or annoying symptoms might spend some time in a neurologist's office before their brain tumor gets diagnosed.
- Neurosurgeon: Probably the first doctor you will meet in the hospital to treat your cancer. Some GBMs are inoperable, but many are not. If you can have surgery to remove your tumor, the neurosurgeon is the person who will perform the operation. Your neurosurgeon will assess you before surgery, perform the operation, follow you in the hospital until you are discharged, and do a follow-up visit to be sure you are healing well after your surgery.
- PET scan: A PET scan is another type of diagnostic imaging which is sometimes done when doctors can't tell whether an enhancement on an MRI is live tumor or not. PET stand for "positron emission tomography." A person takes in, either by drinking or perhaps through an IV, a molecule that a tumor is likely to take up and use, which has a little radioactive "tag" on it. Then the scan is performed. As the radioactive tag breaks down it emits particles called positrons, which are read by the scanner and translated by its computer into a color 3-D image. If the area in question is taking up the test molecule and breaking it down, it can be assumed to be alive, which can help in deciding, for example, if a suspicious area needs to be surgically removed or not.
- Placebo: The fake medicine given in a clinical trial to the group of subjects serving as controls.
- Pseudo-progression: Many times after radiation is completed, we will find it has introduced changes on the MRI that look like tumor but are not tumor. Radiation damages normal cells as well as the bad ones and this can make that first post-radiation MRI, which may be full of pseudo-progression, a little scary. This is how the joke got started that if you switch the first two letters in "nuclear medicine" you get a lot better descriptor of the actual situation. May your pseudo-progression not freak you out.
- Recurrence: What you hope will never happen, but nearly always does. GBM sends tiny tendrils of cancerous cells through the brain tissue. A surgeon is unable to see all of these or remove them during surgery without causing severe brain damage. Sad to say, one of these will sprout a new tumor at some point. When it shows up in the same area as the original tumor, it's called a "recurrence" and when the new tumor is in a different place, it is a "re occurrence." Now that's splitting hairs.
- Radiation oncologist: A medical doctor specializing in the use of radiation to treat cancer. Most GBM patients get at least some radiation therapy. This is the person who will plan your radiation treatments and follow you as you are taking them to make sure you are not experiencing undue side effects.
- Temozolamide: Currently the chemotherapy of choice for GBM. It replaced older drugs such as CCNU starting in about 1999. Older drugs made people sicker and didn't work as well, although when temozolamide fails they are sometimes used as a fallback. Temozolamide comes as both a pill and an injectable and penetrates the blood brain barrier. Most people take the pill form during the six weeks they are receiving radiation, and then in higher doses five days out of every month. When to stop temozolamide is controversial. Temozolamide can drop a person's platelet count and rarely cause other side effects, so most people will have blood drawn before every new course of the drug. It can cause nausea and vomiting, so patients will probably be on a nausea medication such as ondansetron while taking it. There have also been reports of itching and hives, loss of appetite, and a metallic taste in the mouth. The drug is, sad to say, horribly expensive, although a generic has just come on the market. If you are having problems paying for your temozolamide, contact your hospital social worker. Charity programs exist to help people pay for the medicine; one well-known one is the ACT Program. Your social worker should be able to help you apply. Other names for Temozolamide: Temodar, Temodal,Temcad. Temozolamide is a Part B drug for Medicare purposes.
- Titanium plate: Rarely a person may lose a piece of their skull in a traumatic accident, or, even more rarely, thank goodness, brain surgery for GBM. When this happens surgeons will insert a metal plate in place of the skull, in order to protect the brain, usually made of titanium. Please don't freak out; out of close to 1500 GBM fighters to join our site, we've only heard of one who needed a titanium plate!