Tumor 1 Postop
Tumor 2 Preop
Tumor 2 Postop
Tumor 1 Preop
Brain-Lateral View of the Left Side
VIRGINIA BRAIN & SPINE CENTER
|Natural History||1 month|
|with Steroids||2 months|
|with WBRT||3-6 months|
|with Surgery||8 months|
Table demonstrates additive effect of progressively more invasive therapy on median survival after diagnosis
|Low Grade||16%||34||5-10 years|
Table depicts median age at diagnosis and median survival (50% of patients are below and 50% are above these numbers)
The brain is perhaps the most complex part of the human body. It is composed of neurons which transmit signals between the different parts of the brain as well as to and from the body. The majority of the cells in the brain, however, are supportive in nature and are called glial cells. The brain can be divided into parts based on location and function as described below. Within the middle of the brain are fluid-filled cavities called the ventricles. The brain is completely surrounded in cerebrospinal fluid which is primarily made and circulated within these ventricles. In general, the right half of the brain controls the left part of the body and the left half of the brain controls the right part of the body. In most people, language function is located in the left side of the brain, or they are left-side dominant. Approximately 10% of left-handed people have language function at least partly located in the right side as well.
Signals are transmitted between the brain and the body through the neurons with multiple stops in between. The brain transmits information and instructions from the cerebral cortex with stops in the deep nuclei, brain stem, spinal cord, and finally to the peripheral nerves in that order. The body sends information back to the brain in the opposite direction through the same stops. The deep nuclei are essentially relay stations or pit stops between the cerebral cortex and brain stem. They include the thalamus and basal ganglia. The brain stem is essentially a relay station between the spinal cord and higher brain areas. It houses important centers for the "lower functions" of the brain that are shared among all creatures with a brain - breathing, alertness, reflexes, etc. Another important structure within the brain is the cerebellum which sits behind the brain stem. The cerebellum primarily functions to fine tune our movements and coordination with direct input to the brain stem and deep nuclei.
Most tumors that occur in the adult brain have spread there from somewhere outside of the brain. That is, most adult brain tumors are metastatic tumors from cancers such as lung, breast, or melanoma. The most common tumors that occur de novo within the brain are derived from glial cells and are therefore called gliomas. The second most common type of primary brain tumor is derived from the membrane that surrounds the brain called the meninges. Therefore, these tumors are called meningiomas and actually occur along the surface of the brain. The symptoms caused by a brain tumor are not determined by what kind of tumor it is but rather by how fast it is growing and where it is located. A tumor that grows very slowly may become quite large before causing any symptoms because the brain will learn to adapt to it over time. However, a small tumor in a very important part of the brain can cause significant symptoms before too long at all. The most common symptoms of a brain tumor include headache, nausea, seizure, and focal neurological deficits such as weakness or numbness.
The cerebral cortex is the neural tissue along the surface of the brain. This is where all of the "higher functions" of the brain are controlled. There are four lobes that make up the cerebral cortex on each side of the brain. Each bump on the surface of the brain is called a gyrus. Each groove between the gyri is called a sulcus. An important landmark is the central sulcus that separates the frontal lobe from the parietal lobe. A deep groove is called a fissure and there are two important ones - the interhemispheric fissure separates the two halves of the brain and the sylvian fissure separates the temporal lobe from the frontal and parietal lobes.
The frontal lobe is the part of the brain in front of the central sulcus. Most of the frontal lobe is involved in complex planning and execution of motor functions. The gyrus in front of the central sulcus, the pre-central gyrus, is the primary motor cortex. Injury to this part of the brain causes loss of strength on the opposite side of the body. The primary motor cortex is considered to be an eloquent area of cortex meaning that injury will cause significant neurological dysfunction. Tumors that occur in the primary motor cortex require special techniques in order to remove them safely without causing paralysis. A small part of the frontal lobe on the dominant side near the sylvian fissure also helps coordinate the motor processing and output of speech. Injury to this area of the brain will cause difficulty forming words and speaking with the preserved ability to understand speech. The frontal lobe also affects personality and used to be the target of "frontal lobotomies".
The temporal lobe is involved in language, hearing, and memory. Language and memory function is primarily on the left side in most people but up to 10% of left handed individuals also have language and memory function in the right temporal lobe as well. The dominant temporal lobe is considered to be an eloquent area of cortex. Tumors that occur in the temporal lobe often require special studies and techniques in order to remove them safely without causing language or memory problems. The primary auditory cortex is in both temporal lobes but injury to one side typically does not cause any hearing loss because each ear sends sound information to both sides of the brain.
The parietal lobe is mostly involved in complex processing of sensory information. The primary sensory cortex is located immediately behind the central sulcus in the post-central gyrus. A small part of the parietal lobe on the dominant side near the sylvian fissure helps process the ability to understand and formulate language information. Injury to this area of the brain will cause the inability to understand speech or to speak coherently. Injury to the rest of the parietal lobe will often cause difficulty processing information from the opposite side of the body and environment. Therefore, patients may neglect information from that side as if it is not there.
The occipital lobe is mostly involved in processing of visual information. The primary visual cortex is located in the very back of the occipital lobe. Injury to specific parts of the occipital lobe can cause different types of visual impairment. Similar to the rest of the brain, each occipital lobe processes visual information from the opposite side. Therefore, injury to the right occipital lobe will impair processing of visual information from the left side of the patients visual field and vice versa with injury to the left occipital lobe.
The cerebellum sits directly behind the brain stem. The cerebellum primarily functions to fine tune movements and coordination with direct input to the brain stem and deep nuclei. Injury to the cerebellum often causes incoordination and poor balance. This is usually temporary and resolves over the course of months as the brain learns to adapt. The cerebellum is a common location formetastatic tumors and hemorrhagic strokes. This is a dangerous location for tumors and strokes because it can put direct pressure on the brain stem leading to life threatening complications. Surgery is therefore often performed to relieve pressure caused by tumors or strokes in this location.
Gliomas are tumors formed from the supportive cells in the brain known as glial cells. One of the more common types of glial cells are call astrocytes and tumors that arise from these cells are therefore called astrocytomas. Astrocytomas are the most common primary brain tumor in adults. 12,000 new cases occur each year in the United States alone. They can occur anywhere within the brain but are most common in the frontal and temporal lobes. These are classified as either low grade or high grade and their grade correlates strongly with survival. High grade gliomas are either anaplastic astrocytomas or glioblastoma multiforme (GBM) based on cellular characteristics on pathology. These tumors typically do not spread outside of the brain but are very infiltrative with a tendency to recur at the original site they are found at. Unfortunately, most newly diagnosed astrocytomas are high grade. Standard treatment includes maximal surgical resection followed by radiation and chemotherapy. Although there is currently no "cure" for high grade gliomas there are long term survivors. There are a number of ongoing clinical trials.
Gliomas are infiltrative tumors often with no clear borders separating them from normal tissue and with significant swelling around the tumor. Symptoms will often improve with steroids alone by decreasing the swelling around the tumor. In addition to steroids, patients are often started on medicines that will minimize the risk of seizures. The goal of surgery is to remove as much of the tumor as possible without causing new neurological symptoms. Even with complete removal of the tumor based on visual inspection and postoperative imaging studies these tumors infiltrate within the normal tissue and tumor cells are always left behind. Therefore, radiation and chemotherapy are used after surgery to slow the growth of remaining cells. If the tumor is located near language or motor areas of the brain then special techniques are required to remove them safely. Cortical motor mapping can be performed with the patient asleep or awake but speech mapping can only be done with an awake craniotomy. There are a few areas within the brain that are typically too dangerous for surgical resection including the brain stem, deep nuclei, and thalamus.
There are many factors that determine survival. Each patient is different and statistics can not be directly applied to an individual person. General factors that improve survival are lower grade of the tumor, gross total resection of the tumor radiographically, younger age, good functional status and health, and genetic factors that determine response to radiation and chemotherapy.
Meningiomas are tumors formed from the cells that make up the membrane that surrounds the entire brain called the meninges. These tumors therefore form on the surface of the brain. Although they can grow and push into the brain they typically do not infiltrate and grow through the brain like gliomas. These are almost always benign tumors that grow very slowly over time. If they grown large enough they will ultimately cause symptoms like any other brain tumor. Symptoms will often improve with steroids alone by decreasing the swelling around the tumor. In addition to steroids, patients are often started on medicines that will minimize the risk of seizures. Small meningiomas are often asymptomatic and do not necessarily require any treatment. Larger tumors or those that are causing symptoms are often treated with surgery. Patients with small tumors or those who are too sick for surgery will often be observed over time or treated with radiation or radiosurgery.
Meningiomas account for 15-20% of all brain tumors in adults. About 13,000 new meningiomas are diagnosed each year in the United States. They are twice as common in women than in men and they are most commonly found at the age of 40 or 50 years old. There is over a 90% long-term survival rate for patients with meningiomas. The Meningioma Project offers support and further information for patients with this common brain tumor.
The most common type of tumor to occur in the adult brain is one that spreads there from outside of the brain. Over 100,000 new cases of brain metastasis occur each year in the United States. A patient with cancer in another part of the body, such as the lung, breast, or skin, may have cancer cells spread through the blood and grow in other parts of the body such as the brain. These tumors that spread are called metastatic tumors and a patient may have one or more metastatic tumors grow in the brain in this manner. They often grow near the surface of the brain and push the normal tissue away instead of infiltrating through the tissue as a glioma does. Surgery on brain metastases may be recommended to improve survival and/or symptoms. If there are too many tumors or surgery would be too dangerous then surgery may not be warranted.
Up to 30% of patients with cancer will develop metastases to the brain. Up to 10% of patients with cancer will initially present with symptoms due to a brain metastasis. Symptoms will often improve with steroids alone by decreasing the swelling around the tumor. In addition to steroids, patients are often started on medicines that will minimize the risk of seizures.
There are many factors that determine survival. Each patient is different and statistics can not be directly applied to an individual person. General factors that improve survival are type of primary tumor, amount of systemic disease, fewer number of brain metastases, good functional status and health, and factors that determine response to radiation and chemotherapy.
Pituitary adenomas are benign tumors that grow from the pituitary gland. The pituitary gland is located under the brain and right behind the optic nerves. Patients with pituitary adenomas often present with symptoms due to hormone problems or with vision loss due to pressure on the optic nerves. These tumors grow very slowly over time. Sometimes, they can be treated with medicine alone. If they are large or not responsive to medical therapy then surgery is often recommended.
Brain tumors often present with symptoms but are not diagnosed until some form of imaging study demonstrates their presence. Once a study demonstrates the presence of a brain tumor, other studies are sometimes obtained to evaluate other characteristics that may help diagnose the type of tumor or plan surgical treatment. A brain CT or MRI can also be processed through a computer program to generate a model that can show a surgeon where the tumor is when they point to a spot on the surface of the head.
CT: A brain CT (Computed Tomography or "CAT" scan) is often obtained first. This is a computer generated image formed from a series of multiple xrays taken in close succession through the head. This is a quick and easy study to obtain that often takes less than ten minutes of imaging time. This characterizes tissues of different densities very well such that the brain is well visualized compared to the surrounding bone and internal fluid spaces. A tumor is often a different density than the normal brain and may cause distortion of the normal symmetric anatomy of the brain. Contrast is often added intravenously to better visualize a tumor. Contrast is dense material that flows in the blood and since tumors often have a large blood supply they may become more bright with the addition of contrast. This study is relatively poor resolution but is the preferred study for initial assessment, for evaluating calcification which may occur in some slow growing tumors, and for evaluating new bleeding within a tumor.
MRI: a brain MRI (Magnetic Resonance Imaging) is almost always obtained to better characterize the tumor. This is a high resolution image formed by taking advantage of the different magnetic characteristics of various tissue types. This is a longer study that can take more than 45 minutes of imaging time. This offers much better images of the brain than CT does. This study not only visualizes brain from the surrounding bone and internal fluid spaces but also details the specific anatomy within the brain. A tumor that may not be seen on CT will show up on an MRI. Contrast is often added to better visualize the tumor. Contrast is dense material that flows in the blood and since tumors often have a large blood supply they may become more bright with the addition of contrast. This study is the preferred method for evaluating brain tumors. Patients with pacemakers or other sources of metal within the body may not be able to obtain an MRI.
Angiogram: A brain angiogram is a study that visualizes the blood vessels within the brain. A conventional angiogram involves injecting contrast dye from within the artery (usually accessed in the femoral artery at the groin) and then taking xrays of the head. This is the oldest and still probably the best way to image the blood vessels within the brain. A CT or MRI can also be processed in such a way as to generate relatively good representations of the blood vessels as well. An angiogram is often obtained to determine the exact blood supply of the tumor. Sometimes the blood supply can be embolized, or obstructed, before surgery to make resection safer and easier. This is most often done for meningiomas.
A craniotomy is an open exposure of the brain in order to operate on it. This involves making an incision in the skin and removing a portion of the skull. The membrane surrounding the brain is opened and the brain is directly visualized. When surgery on the brain is completed, the surrounding membrane is closed and the bone that was removed is returned to its original position and fastened in place with titanium plates and screws. The skin is typically closed with staples or sutures and gauze wrap is placed around the head. Computer image guidance is typically used to create a smaller incision and to help guide the surgery. Computer image guidance involves creating a three-dimensional representation of the patient's head and brain using MRI or CT images.
Following a craniotomy, a patient will spend at least one night in the Intensive Care Unit for close neurological monitoring. If there are no complications, a patient may be discharged from the hospital as early as 2-3 days following a craniotomy. Most patients will be placed on a tapering dose of a steroid to minimize swelling and another medicine to prevent seizures. If other therapies are needed, such as chemotherapy or radiation, then these will generally be started 2-3 weeks after the surgery in order to allow for proper healing.
A craniotomy is generally a safe procedure and outcomes are often more related to how a patient is doing before the surgery. The risk of a major complication following most craniotomy cases is well under 5% overall. These risks include infection or bleeding in the brain, stroke, or new neurological deficits. There are specific risks that depend on the specific part of the brain being operated on and some cases obviously have higher risks than others. Special techniques are often employed for areas that are considered "eloquent" such as those for language or motor functions.
An awake craniotomy may be performed for tumors or other lesions that are located in or near parts of the brain that have important motor or language functions. Amazingly, the brain does not have any pain receptors and this kind of surgery is very well-tolerated. This procedure is most commonly performed to monitor a patient's ability to move or talk during resection of the brain. Most of the procedure is actually performed while the patient is asleep. After the brain is exposed, the patient is briefly woken up during removal of the abnormality within the brain. Once the resection is completed the patient is again put back to sleep.
Awake craniotomies with cortical mapping have been performed for over fifty years but are not performed at all hospitals with neurosurgery. It is well-established that cerebral cortex with language or motor functions will respond to a small electrical current. By stimulating different areas on the surface of the brain, we can identify which areas are important for moving parts of the body or for language functions. When the cortex responsible for moving a part of the body is stimulated that part of the body will twitch briefly. When the cortex responsible for talking is stimulated specific language function is briefly impaired. Once the parts of the brain vital for these functions are identified, the removal of the tumor can proceed while being careful to preserve the identified structures. Those parts of the brain that do not respond to stimulation can be removed with relative confidence. An awake craniotomy is otherwise like any other craniotomy.
Cortical mapping is the use of a brief electrical current on the surface of the brain in order to identify areas with vital functions. In general, this is performed to identify areas with important motor and language function. Cortical mapping only needs to be performed if the tumor or other abnormality is in or near one of these vital areas of the brain based on preoperative imaging studies. In order to map language function an awake craniotomy must be performed. The patient is asked to talk or perform specific language tasks and when the language parts of the brain are stimulated the patient will be unable to perform the specific tasks. Motor functions can be performed with the patient asleep or awake. When the motor parts of the brain are stimulated the patient will twitch on the opposite side of the body. For greater confidence, the patient can be awake and performing motor tasks during resection the surgery. If the patient is able to function well during and after the resection then vital structures have clearly been preserved.
A transphenoidal resection is a minimally invasive procedure for removal of tumors in the region of the pituitary gland. This surgery is performed through the nose. A small incision is made in the soft tissues along the nasal septum. Instruments are passed through the nose to the back of the nasal cavity. The sphenoid sinus sits behind the nasal cavity. An opening is made into the front of the sphenoid sinus and the mucosa within the sinus is removed. The pituitary gland sits behind the back wall of the sphenoid sinus. A small hole is made in the back of the sinus exposing the gland. The tumor is then removed through the nose and sinus. One of the more common complications following this surgery is leaking of the cerebrospinal fluid through the nose after this surgery. To prevent this, the sphenoid sinus is often obliterated by filling it with fat and blocking the ability of cerebrospinal fluid to flow out. This fat is sometimes obtained through a separate small incision in the abdomen. Once the surgery is done, the nose is packed to prevent bleeding and these packs are typically removed in 1-2 days.
Patients are admitted to the hospital for 1-3 days typically. The pituitary gland secretes a number of important hormones and it is important to monitor for altered hormone function after this surgery. Patients will typically be placed on a steroid before surgery and shortly thereafter. A cortisol (steroid) level is checked and replacement will be stopped if this is normal. Sodium levels are checked closely after this surgery as well. Anti-Diuretic Hormone (ADH) is made by the pituitary gland and loss of this hormone will cause diabetes insipidus. When this happens, water is not retained in the kidneys and sodium levels in the body are high. This hormone can be replaced easily if needed. Once a patient demonstrates that they have retained these hormone functions or are stable with replacement therapy then they can be discharged home. Other hormones can be followed up on an outpatient basis. An endocrinologist is often involved for the care of these hormone issues.
Large tumors sometimes cannot be completely removed with this procedure. If the tumor is very large then a standard craniotomy may be a better option.
A stereotactic brain biopsy is performed to obtain a small tissue sample in order to diagnose the type of tumor within the brain. An MRI or CT scan is obtained and the images are processed through a computer in order to generate a three-dimensional, or stereotactic, model. Using this model, a needle can be guided from the surface of the skull to the middle of the tumor in order to obtain a small specimen.
The patient is brought to the operating room and given anesthesia. The biopsy can be performed with the patient completely under anesthesia or it can be done with the patient awake. If the patient is awake then light sedation and a lot of local anesthetic is given so there is no pain during the procedure. Based on the model, a suitable starting point is selected and the scalp is shaved, sterilized, and anesthetized. A tiny incision is made in the scalp and a small hole is drilled through the skull. Using the model as a guide, the blunt-tipped biopsy needle is gently passed through the brain to the tumor. Specimens are taken and sent to pathology for identification. The needle is removed and the skin is closed with a stitch or staple.
The patient is typically monitored in the ICU for several hours or overnight. This procedure is relatively safe and well-tolerated. The risk of bleeding and new symptoms is under 5% overall. At some centers, this is safely performed on an outpatient basis with observation after the procedure for 6-8 hours. The final diagnosis from pathology will typically take 3-5 days to obtain. Due to the small specimen size a final diagnosis is sometimes not obtained and will require an open biopsy through a standard craniotomy.
Radiosurgery is a non-invasive form of therapy that is sometimes used as an alternative or as a supplement to standard surgery. Unlike standard radiation therapy, radiosurgery uses computer-guided technology to target the tumor for radiation while preserving the surrounding normal brain. This is typically reserved for tumors smaller than 3 centimeters in cross-sectional size (smaller than a golf ball).