Diagnosing Brain Tumours
Identifying a brain tumour usually involves a neurological examination, a brain scan, and/or an analysis of the brain tissue.
Doctors use the diagnostic information obtained in such tests to classify the tumour from the least aggressive (benign) to the most aggressive (malignant).
In most cases, a brain tumour is named for the cell type of origin or its location in the brain. Identifying the type of tumour helps doctors determine the most appropriate course of treatment.
Neurological Examination
A Neurological Examination is a series of tests to measure the function of the patient s nervous system and physical and mental alertness. If responses to the exam are not normal, the doctor may order a brain scan or refer the patient to a neurologist or neurosurgeon, who will then order a Brain Scan.
Identifying a brain tumour usually involves a neurological examination, a brain scan, and/or an analysis of the brain tissue.
Doctors use the diagnostic information obtained in such tests to classify the tumour from the least aggressive (benign) to the most aggressive (malignant).
In most cases, a brain tumour is named for the cell type of origin or its location in the brain. Identifying the type of tumour helps doctors determine the most appropriate course of treatment.
Brain Scan
A Brain Scan is a picture of the internal structures in the brain. A specialized machine takes a scan in much the same way a digital camera takes a photograph. Using computer technology, a scan compiles an image of the brain by photographing it from various angles.
Some types of scans use a contrast agent (or contrast dye), which helps the doctor see the difference between normal and abnormal brain tissue. The contrast agent is injected into a vein and flows into brain tissue. Abnormal or diseased brain tissue absorbs more dye than normal healthy tissue.
The most common scans used for diagnosis are as follows:
MRI (Magnetic Resonance Imaging)
MRI (Magnetic Resonance Imaging) is a scanning device that uses magnetic fields and computers to capture images of the brain on film. It does not use x-rays. It provides pictures from various planes, which permit doctors to create a three-dimensional image of the tumor. The MRI detects signals emitted from normal and abnormal tissue, providing clear images of most tumours.
Before having the scan, you will be given an injection of dye into a vein in the arm, which doesn’t usually cause discomfort. This is called a contrast medium and can help the images from the scan to show up more clearly.
During the test you’ll be asked to lie very still on a couch inside a long cylinder (tube) that is open at both ends. The whole test can take up to an hour. It’s painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you’ll be given earplugs or headphones. You will be able to hear, and speak to, the person operating the scanner.
CT or CAT Scan (Computed Tomography)
CT or CAT Scan (Computed Tomography) combines sophisticated x-ray and computer technology. CT can show a combination of soft tissue, bone, and blood vessels. CT images can determine some types of tumors, as well as help detect swelling, bleeding, and bone and tissue calcification. During the test you will be asked to lie with your head inside an opening in the scanner. The scan is painless but takes longer than a normal x-ray (from 5 to 10 minutes). It may be used to identify the exact area and size of the tumour.
Some people who have a CT scan are given an injection of a liquid into a vein, to allow particular areas of the brain to be seen more clearly. Usually, iodine is the contrast agent used during a CT scan. The injection may make you feel hot all over for a few minutes. Before having the injection, it is important to tell your doctor and the person doing the scan if you are allergic to iodine or have asthma or diabetes.
PET Scan (Positron Emmission Tomography)
PET Scan (Positron Emission Tomography) uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of the mildly radioactive substance is injected into a vein, usually in your arm. Tumours normally absorb more of the glucose and the radioactivity shows up on the scan.
After the injection you may be asked to lie in a dark room with your eyes closed. You’ll then be taken to the scanning room and asked to lie on a couch with the scanning ring around you. The dose of radiation you receive is no more than a normal x-ray.
A PET scan is not routinely used to diagnose a brain tumour but it may help to tell whether a tumour is growing and whether it is cancerous (malignant) or benign. PET scans aren’t available in all hospitals, and you may have to travel to a hospital some distance away from your home to have one.
Analysis of Brain Tissue
A biopsy is a surgical procedure in which a sample of tissue is taken from the tumour site and examined under a microscope. The biopsy will provide information on types of abnormal cells present in the tumour. The purpose of a biopsy is to discover the type and grade of a tumour. A biopsy is the most accurate method of obtaining a diagnosis.
Open Biopsy
An open biopsy is done during a craniotomy. A craniotomy involves removing a piece of the skull in order to get access to the brain. After the tumour is resected (completely removed) or debulked (partially removed), the bone is usually put back into place.
Closed Biopsy
A closed biopsy (also called a stereotactic or needle biopsy) may be performed when the tumour is in an area of the brain that is difficult to reach. In closed biopsy, the neurosurgeon drills a small hole into the skull and passes a narrow hollow needle into the tumour to remove a sample of tissue.
In both cases once a sample is obtained, a pathologist examines the tissue under a microscope and writes a pathology report containing an analysis of the brain tissue. Sometimes the pathologist may not be able to make an exact diagnosis. This may be because more than one grade of tumor cells exists within the same tumor. In some cases, the tissue may be sent to another institution for additional analysis.
**Portions of the above content have been reproduced with the kind permission of the National Brain Tumor Society**
Treatment
Surgery
Surgery is usually the first line of treatment for a brain tumour, with a goal of removing as much visible tumour as possible. Surgeons define an operable, or resectable, tumour as one that can be removed without causing severe damage to surrounding, healthy brain tissue. Surgery is also used to relieve the buildup of cerebrospinal fluid, the fluid that bathes the brain, which can result from the growth of a tumour.
A craniotomy is the most common type of surgery. It involves the removal of a piece of the bone of the skull so that access to the tumor is possible. After surgery, the bone is replaced.
Before a definitive diagnosis can be made, a biopsy is usually performed. A biopsy involves taking a small amount of tissue from the tumour through a very thin needle and then examining it. Pathologists will examine the cells and determine the tumor’s grade, level of malignancy, and exact type. A biopsy is often performed during the actual surgical procedure.
New surgical techniques and tools allow for the precise and safe removal of tumours from many parts of the brain. Surgery may be followed by radiation and/or chemotherapy. You should discuss the risks and benefits of surgery with your medical team.
Radiation
Radiation therapy uses high-energy x-rays or other types of ionizing radiation to stop cancer cells from dividing. It may be used when surgery is not advised, for tumors that cannot be completely resected, or after surgery to prevent or delay tumor recurrence. Radiation therapy can stop or slow the growth of inoperable tumors. Different forms of radiation are used for specific types and sizes of tumors. Use of radiation therapy is avoided in children below the age of three because it damages the developing brain.
Radiation therapy can be delivered by external or internal means. External beam radiation therapy involves linear accelerators and cobalt machines that direct radiation at the tumor from outside the patient’s body. Two of the main types of external beam radiation therapy are conventional and stereotactic radiosurgery.
Conventional radiation therapy delivers radiation to an entire region of the brain. The radiation is fractionated into many small doses and given over a period of time. The radiation is usually administered two to three weeks after surgery and continues for approximately six weeks (excluding weekends), with similar dosages at each visit. Depending on the location and size of the tumor(s), the treatment can be either focused or whole brain radiation therapy (WBRT). Focused radiation therapy aims x-rays at the tumor and area surrounding it. WBRT aims radiation at the entire brain. WBRT is used to treat multiple primary and metastatic brain tumors.
Interstitial radiation therapy (brachytherapy), an internal form of radiation therapy, involves surgically implanting radioactive material directly inside the tumor.
Stereotactic radiosurgery (SRS) provides pinpoint precision in the administering of radiation without any invasive surgery. During stereotactic radiation, a single, high dose of radiation is delivered to the tumor, minimizing damage to the surrounding brain tissue. Stereotactic radiosurgery is done on an outpatient basis. Patients typically receive just one treatment , but in some cases doctors may recommend up to five days in a row of the procedure.
In an SRS procedure, a head frame may be attached to the skull to hold the head completely still during the procedure. Some methods of SRS may use a mask instead of a head frame. Then CT or MRI scans are taken. With the aid of computer imaging, the location of the tumor is accurately calculated. The radiation is delivered directly to the tumor, often from several different directions. Size and location of the tumor are important eligibility criteria for SRS, and not everyone is a candidate.
You may hear different names associated with radiosurgery, including Gamma Knife®, LINAC, X-Knife®, Trilogy®, CyberKnife®, and Novalis®. These are the brand names of the equipment that doctors use to provide the treatment. The core principles are the same with each machine, but they use different sources of energy and different methods to target the tumor.
Chemotherapy
Chemotherapy uses chemicals (drugs) that have a toxic effect on tumor cells as they divide. The drugs interfere with the normal functioning of the rapidly dividing cells of the tumor to prevent tumor growth. Chemotherapy is usually a secondary therapy. It is usually not used for the treatment of noncancerous brain tumors.
Chemotherapy is usually taken orally or by injection, and may be given alone or in combination with other treatments. Chemotherapy is given in cycles, which consist of “on” and “off” phases – days of treatment followed by periods of time between treatments. Cycles vary depending on the drug or drugs used.
Another way to delivery chemotherapy to the brain is through polymer wafer implants. With this method, biodegradable wafers are saturated with a chemotherapy drug, BCNU, and placed directly inside the tumor cavity at the time of surgery. The wafers are left there to dissolve over a short period of time. In this way, a concentrated dose of BCNU (approximately 100 times higher than that tolerated through IV) can be delivered directly to the tumor site without increasing side effects.
Chemotherapy can decrease the chance of a brain tumor spreading outside the nervous system. Chemotherapy has been particularly effective in treating children with brain tumors that have spread outside the brain to the bone or bone marrow. The use of chemotherapy also helps delay or replace the use of radiation treatment in children, which can be harmful to the developing brain.
Medication
The medications most commonly prescribed for brain tumors are steroids for brain swelling (edema) and anti-epileptic drugs to control seizures.
Steroids (glucocortico-steroids) are drugs that reduce edema (swelling) in the brain. Steroids can help relieve pre-surgery symptoms, which may increase the time to make treatment decisions. Steroids may be prescribed at diagnosis, or before or after surgery. Common steroids include dexamethasone (Decadron), prednisone, and methylprednisolone. These drugs do not kill tumor cells, but can improve a patient’s condition. Steroids may be taken alone or combined with other forms of treatment. When the swelling is under control, then the dosage is gradually tapered off.
Steroids have a range of short- and long-term side effects. Common short-term side effects include insomnia, facial swelling and flushing, increased appetite, mood swings, and personality changes. Some people who take steroids for a few days or weeks do not experience side effects; others do. Side effects from long-term use of steroids, for example dexamethasone, may include cataracts, osteoporosis, muscle weakeness and diabetes. Patients should never stop taking steroids without the doctor’s knowledge. Instead, discuss possible side effects with the doctor.
Anti-epileptic drugs (AEDs) are medications used to control seizures. They are also called anticonvulsants, antiseizure drugs, and epilepsy drugs. A patient may be put on AEDs if he or she experiences a seizure or as a precautionary measure. Some common AEDs are phenytoin (Dilantin), carbamazepine (Tegretol), valproate (Depakote), levetiracetam (Keppra), gabapentin (Neurontin), topiramate (Topomax), and lamotrigine (Lamictal). The type and amount of medication is based on the level of seizure control needed and the side effects from the medication. Common side effects may include fatigue, weakness, nausea and lack of balance or coordination. A rash is an allergic reaction, and the patient must see a doctor immediately.
If the patient has not experienced seizures or if the person is seizure-free for an extended period of time, the AED may be tapered off. AEDs should never be stopped abruptly.It is important to remember that side effects of these AEDs vary greatly from person to person. If side effects are a serious problem, a doctor may change a patient’s medication.
Many medications will either increase or reduce the effect of AEDs. Some chemotherapy drugs may interact with AEDs and change the effectiveness of either or both drugs. Blood tests and other methods are used to monitor possible drug interactions.
To help your doctors recognize possible drug interactions, keep a list of all medications, including over-the-counter products. Also, keep track of symptoms that may be possible side effects.
Molecularly Targeted Therapy
A molecularly targeted therapy is a medication that blocks or inhibits an important cancer molecular abnormality, thus reducing the cancer’s destructive behavior
Molecular abnormalities are aspects of cells that are not normal. For example, these abnormalities control how cancer cells abnormally grow and divide; aggressively spread and invade; survive and live much longer than normal cells; and make new blood vessels (angiogenesis) required for tumor growth. Blocking abnormal molecules can lead to the death of cancer cells.
Molecularly targeted medicines are sometimes called “smart” medicines because of their ability to hone in on tumor cells while sparing healthy cells. The FDA has already approved several promising molecularly targeted therapies for patients with other types of cancer. These medicines are now being evaluated in clinical trials for brain tumor patients. Bevacizumab is one drug in particular that is being extensively evaluated in a number of studies.
Because these medications are specific to cancer cells, they have fewer side effects than traditional chemotherapy drugs. At some point in the future, doctors may be able to study each patient’s tumor in the laboratory and determine exactly which molecular abnormalities are present. With that information, the molecularly targeted therapy or regimen best suited to patient could be prescribed.
Complementary/Alternative
Complementary therapies are those that are not currently part of conventional medicine, but have demonstrated a favorable risk/benefit ratio to be used as part of supportive care. There are also alternative therapies, those which are promoted to be used in place of standard medical care. Together they are called CAM, for complementary and alternative medicine.
Some different types of complementary therapies include:
- Mind-body interventions: meditation, imagery, relaxation
- Biologically-based treatments: melatonin, herbals, mushrooms, high-dose vitamins, enzyme therapy, botanicals
- Manipulative and body-based approaches: massage, manipulation, chiropractics, yoga
- Energy therapies: Qigong, Reiki, therapeutic touch, distant healing
- Acupuncture
It is important to know that although complementary therapies can be a very helpful part of the overall cancer treatment plan, they can not cure cancer. On the other hand, patients should consider complementary therapies which empower them to take an active part in self care and help them go through cancer treatment. It is important that patients communicate with the health care team about any complementary therapies they are considering, as interactions may occur with standard treatments, such as chemotherapy.
The Ronnie Fehily Foundation CHY20506. Founded in 2012 by a small group of people caring for a family member who was sadly lost to a Brain Tumour.
Support & Information
Latest News & Events
Donate
Brain Tumour Ireland is a registered charity (Registered Charity Number: 20102128 / Revenue Number: 20506).
A little goes a long way and allows us to help and provide support for people and families directly affected by brain tumours.