Brain tumor

What is brain tumor?

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain (secondary, or metastatic, brain tumors).

How quickly a brain tumor grows can vary greatly. The growth rate as well as location of a brain tumor determines how it will affect the function of your nervous system.

Brain tumor treatment options depend on the type of brain tumor you have, as well as its size and location.

Types of Brain Tumors

A brain tumor, known as an intracranial tumor, is an abnormal mass of tissue in which cells grow and multiply uncontrollably, seemingly unchecked by the mechanisms that control normal cells. More than 150 different brain tumors have been documented, but the two main groups of brain tumors are termed primary and metastatic.

Primary brain tumors include tumors that originate from the tissues of the brain or the brain’s immediate surroundings. Primary tumors are categorized as glial (composed of glial cells) or non-glial (developed on or in the structures of the brain, including nerves, blood vessels and glands) and benign or malignant.

Metastatic brain tumors include tumors that arise elsewhere in the body (such as the breast or lungs) and migrate to the brain, usually through the bloodstream. Metastatic tumors are considered cancer and are malignant.

Metastatic tumors to the brain affect nearly one in four patients with cancer, or an estimated 150,000 people a year. Up to 40 percent of people with lung cancer will develop metastatic brain tumors. In the past, the outcome for patients diagnosed with these tumors was very poor, with typical survival rates of just several weeks. More sophisticated diagnostic tools, in addition to innovative surgical and radiation approaches, have helped survival rates expand up to years; and also allowed for an improved quality of life for patients following diagnosis.

Types of Benign Brain Tumors

• Chordomas are benign, slow-growing tumors that are most prevalent in people ages 50 to 60. Their most common locations are the base of the skull and the lower portion of the spine. Although these tumors are benign, they may invade the adjacent bone and put pressure on nearby neural tissue. These are rare tumors, contributing to only 0.2 percent of all primary brain tumors.
• Craniopharyngiomas typically are benign, but are difficult tumors to remove because of their location near critical structures deep in the brain. They usually arise from a portion of the pituitary gland (the structure that regulates many hormones in the body), so nearly all patients will require some hormone replacement therapy.
• Gangliocytomas, gangliomas and anaplastic gangliogliomas are rare tumors that include neoplastic nerve cells that are relatively well-differentiated, occurring primarily in young adults.
• Glomus jugul aretumors most frequently are benign and typically are located just under the skull base, at the top of the jugular vein. They are the most common form of glomus tumor. However, glomus tumors, in general, contribute to only 0.6 percent of neoplasms of the head and neck.
• Meningiomas are the most common benign intracranial tumors, comprising 10 to 15 percent of all brain neoplasms, although a very small percentage are malignant. These tumors originate from the meninges, the membrane-like structures that surround the brain and spinal cord.
• Pineocytomas are generally benign lesions that arise from the pineal cells, occurring predominantly in adults. They are most often well-defined, noninvasive, homogeneous and slow-growing.
• Pituitary adenomas are the most common intracranial tumors after gliomas, meningiomas and schwannomas. The large majority of pituitary adenomas are benign and fairly slow-growing. Even malignant pituitary tumors rarely spread to other parts of the body. Adenomas are by far the most common disease affecting the pituitary. They commonly affect people in their 30s or 40s, although they are diagnosed in children, as well. Most of these tumors can be treated successfully.
• Schwannomas are common benign brain tumors in adults. They arise along nerves, comprised of cells that normally provide the “electrical insulation” for the nerve cells. Schwannomas often displace the remainder of the normal nerve instead of invading it. Acoustic neuromas are the most common schwannoma, arising from the eighth cranial nerve, or vestibularcochlear nerve, which travels from the brain to the ear. Although these tumors are benign, they can cause serious complications and even death if they grow and exert pressure on nerves and eventually on the brain. Other locations include the spine and, more rarely, along nerves that go to the limbs.

Types of Malignant Brain Tumors

Gliomas are the most prevalent type of adult brain tumor, accounting for 78 percent of malignant brain tumors. They arise from the supporting cells of the brain, called the glia. These cells are subdivided into astrocytes, ependymal cells and oligodendroglial cells (or oligos). Glial tumors include the following:

• Astrocytomas are the most common glioma, accounting for about half of all primary brain and spinal cord tumors. Astrocytomas develop from star-shaped glial cells called astrocytes, part of the supportive tissue of the brain. They may occur in many parts of the brain, but most commonly in the cerebrum. People of all ages can develop astrocytomas, but they are more prevalent in adults — particularly middle-aged men. Astrocytomas in the base of the brain are more prevalent in children or younger people and account for the majority of children’s brain tumors. In children, most of these tumors are considered low-grade, while in adults, most are high-grade.
• Ependymomas are derived from a neoplastic transformation of the ependymal cells lining the ventricular system and account for two to three percent of all brain tumors. Most are well-defined, but some are not.
• Glioblastoma multiforme (GBM) is the most invasive type of glial tumor. These tumors tend to grow rapidly, spread to other tissue and have a poor prognosis. They may be composed of several different kinds of cells, such as astrocytes and oligodendrocytes. GBM is more common in people ages 50 to 70 and are more prevalent in men than women.
• Medulloblastomas usually arise in the cerebellum, most frequently in children. They are high-grade tumors, but they are usually responsive to radiation and chemotherapy.
• Oligodendrogliomas are derived from the cells that make myelin, which is the insulation for the wiring of the brain.

Other Types of Brain Tumors

• Hemangioblastomas, usually found in the cerebellum, are slow growing tumors. They come from blood vessels, can be large in size, and are often followed by a cyst. In people aged 40 to 60, these tumors are most common and are more prevalent in men than in women.
• Rhabdoid tumors are rare tumors that are extremely aggressive and tend to spread throughout the central nervous system. They often appear in the body at multiple sites, particularly in the kidneys. They are more prevalent in young children, but in adults, they can also occur.

Pediatric Brain Tumors

Typically, brain tumors in kids come from different tissues than those that affect adults. Treatments that are fairly well tolerated by the adult brain (such as radiation therapy) can prevent a child’s brain from developing normally, particularly in children younger than five years of age.

Around 4,200 children in the U.S. are diagnosed with a brain tumor, according to the Pediatric Brain Tumor Foundation. 72% of kids diagnosed with a brain tumor are younger than 15 years old. In the posterior fossa (or back) of the brain, the majority of these brain tumors grow. Children often have hydrocephalus (a build-up of fluid in the brain) or the face or body does not function properly.

In children, certain types of brain tumors are more common than in adults. Medulloblastoma, low-grade astrocytoma (pilocytic), ependymoma, craniopharyngioma and brain stem glioma are the most common types of pediatric tumors.

A grading system to indicate the malignancy or benignity of a tumor based on its histological features under a microscope has been developed by the World Health Organization (WHO).

• Most malignant
• Rapid growth, aggressive
• Widely infiltrative
• Rapid recurrence
• Necrosisprone

Primary Brain Tumor Types

The types of cells within the tumor categorize brain tumors. Each type of brain tumor develops in a particular way and is treated. Most forms of brain tumors, although meningiomas are more common in women, are significantly more common in men than in women.

Craniopharyngioma

Non-cancerous, slow growing tumors found near the pituitary gland are craniopharyngiomas. In children and middle-aged adults, craniopharyngioma usually occurs. Part solid and part fluid-filled cyst may be the tumor itself. Symptoms can include changes in vision and slow growth caused by the pituitary gland effect of the tumor. These tumors mainly require advanced surgery and likely post-surgery radiation therapy.

Dermoid cysts and epidermoid tumors

Benign growths that develop from epithelial cells that form the outer layer of the body and line some organs and glands are dermoid cysts and epidermoid tumors.

They may grow, including the central nervous system, in different parts of the body. They both grow slowly, and often have not been seen for decades. Via surgical removal, they are treated.

Glioma

Gliomas are a class of brain tumors that are primary. They are some of the brain tumors with the fastest growth. The various types of gliomas include:

• Astrocytoma: Astrocytomas spread throughout the brain and mix with healthy tissue, making them difficult to treat. There are several types of astrocytoma:
  • Low-grade astrocytomas: These include grade I pilocytic astrocytoma and grade II diffuse astrocytoma. Grade I astrocytomas are rarely seen in adults.
  • Anaplastic astrocytoma: Grade III astrocytomas are known as anaplastic astrocytoma. These tumors are aggressive, high-grade cancers.
  • Glioblastoma: Grade IV astrocytomas are called glioblastoma or GBM. Glioblastoma is the most common malignant (cancerous) adult brain tumor and one of the fastest-growing tumors of the central nervous system.
• Ependymoma: Ependymomas arise from ependymal cells that line the brain ventricles and the spinal cord center. The ventricles are brain chambers that generate and transport cerebrospinal fluid, which surrounds the brain and protects it. Ependymomas can be found in the spine or in the brain. Ependymomas in children are more commonly seen and are rare in adults.
• Oligodendroglioma: Oligodendroglioma is generally slow growing. It can be diagnosed as a grade II or grade III tumor.

Hemangioblastoma

From the cells of blood vessels, these slow-growing tumors develop. Typically, hemangioblastoma forms in the brainstem and cerebellum, but may occur in other places, including the retina. Von Hippel Lindau disease, a genetic condition linked to the development of multiple types of tumors and cancers, is associated with about a quarter of the cases.

Medulloblastoma

Medulloblastoma is the most common pediatric malignant brain tumor.

Meningioma

The most common primary brain tumour is meningioma. In meninges, the protective layer of tissue surrounding the brain and spinal cord, these tumors develop from cells. Most are slow-growing and benign. Some are malignant and aggressive, though. Typically, surgery is the first treatment for meningiomas that develop and cause symptoms.

Pineal Gland Tumors

The pineal gland is located deep in the brain and produces the hormone melatonin, that regulates sleep. Pineal gland tumors can be benign or malignant. Pineocytoma and pineoblastoma include pineal tumors.

Pituitary Tumors

Pituitary tumors are generally benign (non-cancerous) growths of the pituitary gland, also called pituitary adenomas. A key part of the endocrine system, which controls development, is the pituitary gland. On our pituitary tumor page, learn more.

Sarcoma

Sarcomas, including cartilage, fat and muscle, are a broad category of tumors that form in the bones and soft tissues of the body. There are more common soft tissue sarcomas than bone sarcomas. Types of bone sarcoma include the sarcoma and osteosarcoma of Ewing. Some gliomas have characteristics similar to sarcomas and are called gliosarcomas. Similar to glioblastomas, gliosarcomas act aggressively.

Sarcomas, including chordoma, may also be found in the spine or skull base. Chordomas are rare tumors of sarcoma that grow at the base of the spine of the skull and bones. Doctors believe that they develop from the leftover cells that when the patient was a developing embryo, served as the framework for the skull base and spine. They can push into the brain and cause many of the same symptoms as brain tumors when chordomas form in the skull, including headaches, dizziness and confusion. Multiple critical nerves and arteries can be involved in chordomas, making them hard to treat. Treatment may require the use of specialized surgery, radiation therapy and/or chemotherapy.

Primary Brain Tumor Risk Factors

A risk factor is anything that increases your likelihood of getting a brain tumor. Research is ongoing into the causes of brain tumors and their risk factors. Although no definite risk factors for brain tumors have been found, some factors may put you at increased risk, including:

• Prior radiation exposure to the brain, often as treatment for another cancer
• Family history of certain conditions including:
  • Neurofibromatosis type 1 and type 2
  • Tuberous sclerosis
  • von Hippel-Lindau disease
  • Li-Fraumeni syndrome

If you have a family history of the conditions listed above, some types of brain tumors may be passed down from one generation to the next. For you, genetic counseling may be right. On our genetic testing page, learn more about the threat to you and your family.

Symptoms of brain tumor

The symptoms vary depending on the location of the brain tumor, but various types of brain tumors may be accompanied by the following:

• Headaches that may be more severe in the morning or awaken the patient at night
• Seizures or convulsions
• Difficulty thinking, speaking or articulating
• Personality changes
• Weakness or paralysis in one part or one side of the body
• Loss of balance or dizziness
• Vision changes
• Hearing changes
• Facial numbness or tingling
• Nausea or vomiting, swallowing difficulties
• Confusion and disorientation

Diagnosis of brain tumor

Sophisticated methods of imagery can identify brain tumors. Computed tomography (CT or CAT scan) and magnetic resonance imaging (MRI) are diagnostic instruments (MRI). Based on the location of the normal nerve pathways of the brain, other MRI sequences can help the surgeon plan the tumor resection. Intraoperative MRI is also used to guide biopsies of tissues and tumor removal during surgery. The chemical profile of the tumor is examined and the nature of the lesions seen on the MRI is determined by magnetic resonance spectroscopy (MRS). Recurring brain tumors can be detected by positron emission tomography (PET scan).

Sometimes the only way to make a definitive diagnosis of a brain tumor is through a biopsy. The neurosurgeon performs the biopsy and the pathologist makes the final diagnosis, determining whether the tumor appears benign or malignant, and grading it accordingly.

Brain Tumor Treatment

Brain tumors (whether primary or metastatic, benign or malignant) are usually treated alone or in various combinations, with surgery, radiation, and/or chemotherapy. While it is true that radiation and chemotherapy are more frequently used for malignant, residual or recurrent tumors, decisions are made on a case-by-case basis and depend on a number of factors as to what treatment to use. There are risks associated with each type of therapy and side effects.

Brain tumor surgery

Complete or almost complete surgical removal of a brain tumor is generally accepted to be beneficial for a patient. The challenge of the neurosurgeon is to remove as much tumor as possible without injuring brain tissue that is important for the neurological function of the patient (such as the ability to speak, walk, etc.). Traditionally, during a craniotomy, neurosurgeons open the skull to ensure they can reach the tumor and extract as much of it as possible. At the time of surgery, a drain (EVD) can be left in the brain fluid cavities to drain the normal brain fluid as the brain recovers from the surgery.

Another frequently done procedure, often prior to a craniotomy, is called a stereotactic biopsy. In order to make an accurate diagnosis, this smaller procedure helps physicians to collect tissue. A frame is normally connected to the head of the patient, a scan is obtained, and the patient is then taken to the operation room, where a small hole is drilled in the skull to allow access to the abnormal area.

Some hospitals can do this same procedure without the use of a frame, depending on the position of the lesion. For analysis under the microscope, a small sample is collected.

Computerized devices called surgical navigation systems were implemented in the early 1990s. The neurosurgeon was supported by these devices with direction, localization and tumor orientation. This knowledge minimized the risks and increased the degree of removal of the tumor. In certain cases, surgical navigation systems have enabled excision of previously inoperable tumors with appropriate risks. Without needing to connect a frame to the skull, some of these devices may also be used for biopsies. One drawback of these systems is that they use a scan (CT or MRI) obtained to direct the neurosurgeon prior to surgery. Thus, they are unable to account for brain movements that can occur intraoperatively.

To help update the navigation device data during surgery, investigators are designing techniques using ultrasound and conducting surgery on MRI scanners.

For patients with tumors affecting language function, such as large, dominant-hemisphere gliomas, intraoperative language mapping is seen by some as a critically important technique. Operating on a conscious patient and mapping the anatomy of their language activity during the operation are included in this technique. Then the doctor determines which parts of the tumor are healthy for resection. Recent studies have determined that cortical language mapping can be used to improve glioma resection while maintaining critical language sites as a secure and successful adjunct.

For certain brain tumor patients, ventriculoperitoneal shunting may be needed. Inside the brain and spine, everybody has cerebrospinal fluid (CSF) that is steadily flowing all the time. The sacs holding the fluid (the ventricles) may become swollen if this flow is blocked, causing increased pressure inside the brain, resulting in a disorder called hydrocephalus. Hydrocephalus can cause brain damage and even death if left untreated. To redirect the spinal fluid away from the brain and thereby reduce the pressure, the neurosurgeon may decide to use a shunt. The peritoneal cavity is typically the body cavity from which the CSF is redirected (the area surrounding the abdominal organs). Usually, the shunt is permanent. If it is blocked, the symptoms are close to those of the original hydrocephalus disorder and can include, among others, headaches, vomiting, vision difficulties and/or fatigue or lethargy. Endoscopic Third Ventriculostomy is another procedure that can be used to monitor blocking of the channels of brain fluid. Without the need for a shunt, this lets the brain fluid be redirected through the obstruction.

Radiation therapy in brain tumor

In order to destroy cancer cells and abnormal brain cells and shrink tumors, radiation therapy uses high-energy X-rays. If the tumor can not be treated adequately by surgery, radiation therapy may be an alternative.

• A number of radiation beams are used for Standard External Beam Radiotherapy to establish a conformal coverage of the tumor while limiting the exposure to surrounding normal structures. With advanced delivery systems, the probability of long-term radiation injury is very low. Aside from 3-dimensional conformal radiotherapy (3DCRT), modern delivery methods include intensity-modulated radiotherapy (IMRT).
• A particular type of radiation in which protons, a source of radioactivity, are aimed directly at the tumor, is used in Proton Beam Therapy. The gain is that harm is caused by less tissue surrounding the tumor.
• Stereotactic Radiosurgery (such as Gamma Knife, Novalis and Cyberknife) : It is a technique which focuses on the target tissue with many distinct beams of radiation. This procedure appears to do less damage to the adjacent tissues of the tumor. There is currently no evidence to indicate that one delivery method in terms of clinical results is superior to another, and each has its advantages and disadvantages.

Chemotherapy in brain tumor

Chemotherapy for particular pediatric tumors, lymphomas, and some oligodendrogliomas is usually considered efficient. While chemotherapy has been shown to improve overall survival in patients with the most malignant primary brain tumors, it does so in only about 20% of all patients, and it is not easy for doctors to predict which patients will benefit prior to treatment. As such, due to the possible side effects, some doctors prefer not to use chemotherapy (lung scarring, suppression of the immune system, nausea, etc.).

Chemotherapy operates by causing damage to the cells that normal tissue repairs better than tumor tissue. Chemotherapy resistance may include the survival of tumor tissue that is unable to respond to the drug, or the drug’s inability to move into the brain from the bloodstream. There is a special barrier called the blood-brain barrier between the bloodstream and brain tissue. By destroying this barrier or by injecting the drug into the tumor or brain, some investigators have attempted to enhance the effect of chemotherapy. The purpose of another drug class is not to destroy the tumor cells, but rather to block further growth of the tumor. Development inhibitors (such as the breast cancer treatment drug Tamoxifen) have been used in some cases to try to stop tumors from developing that are resistant to other treatments.

In 1996, the U.S. The use of chemotherapy-impregnated wafers, which can be used by a neurosurgeon at the time of surgery, has been approved by the Food and Drug Administration. The wafers slowly secrete the medication into the tumor, and with the systemic side effects of treatment, the patient receives chemotherapy.

Visualase

Laser thermal ablation is a newer technique used by some centers to treat smaller tumors, particularly in areas where previous open surgery procedures might be more difficult to reach. This includes inserting a small catheter inside the lesion, possibly performing a biopsy, and then using a laser to thermally ablate the lesion. This technique has been used only recently in the treatment of brain tumors, so long-term efficacy has not been identified.

Investigational Therapies

Many types of new therapies are currently being studied, especially tumors for which the prognosis through established traditional therapies is typically low. Whether these treatments will work is unclear. These treatments are performed in accordance with a protocol and include various types of immunotherapy, selective toxin therapy, anti-angiogenesis therapy, gene therapy, and differentiation therapy. Combinations of therapies may also be able to boost patient outlook, while reducing adverse side effects.

Drugs can be administered directly into the cerebrospinal fluid (CSF, the fluid that bathes the brain and spinal cord) either in the brain or in the spinal canal below the spinal cord for some brain tumors. To assist with this during a minor operation, a thin tube known as a ventricular access catheter may be inserted through a small hole in the skull and into the brain ventricle.

When might chemotherapy be used?

In general, for faster-growing brain tumors, chemo is used. Some types of brain tumors tend to respond to chemo better than others such as medulloblastoma and lymphoma. Chemo is not as effective in the treatment of many other types of cancers, such as tumors of the spinal cord, so it is used less often for these tumors.

Chemo, along with other therapies such as surgery and/or radiation therapy, is most commonly used. Chemo can also be used on its own, especially for tumors that are more advanced or for tumors that have come back after other forms of treatment.

Chemo drugs used to treat brain and spinal cord tumors

Some of the chemo drugs used to treat brain and spinal cord tumors include:

• Carboplatin
• Carmustine (BCNU)
• Cisplatin
• Cyclophosphamide
• Etoposide
• Irinotecan
• Lomustine (CCNU)
• Methotrexate
• Procarbazine
• Temozolomide
• Vincristine

Depending on the type of brain tumor, these medications can be used alone or in combinations. Chemo is delivered in stages, with each treatment phase accompanied by a period of rest to allow the body time to heal. Usually, each cycle lasts for a few weeks.

Carmustine (Gliadel) wafers : The chemo medication Carmustine comprises these dissolvable wafers (BCNU). The wafers should be put directly on or next to the parts of the tumor which can not be removed after the surgeon extracts as much of the brain tumor as is possible during a craniotomy. This form of therapy concentrates the drug at the tumor site, unlike IV or oral chemo that enters all areas of the body, causing little side effects in other parts of the body.

Possible side effects of chemotherapy

Side effects can be triggered by chemo medications. These depend on the form and dosage of medication and the length of treatment. Side effects that are normal can include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Diarrhea
• Increased chance of infections (from having too few white blood cells)
• Easy bruising or bleeding (from having too few blood platelets)
• Fatigue (from having too few red blood cells, changes in metabolism, or other factors)

Some of the most effective drugs against brain tumors tend to have fewer of these side effects than other common chemo drugs. Most side effects usually go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can often help prevent or reduce nausea and vomiting.

Some chemo drugs can also cause other, less common side effects. For example, cisplatin and carboplatin can also cause kidney damage and hearing loss. Your doctor will check your kidney function and hearing if you are getting these drugs. Some of these side effects might last after treatment is stopped.

Be sure to report any side effects to your medical team while getting chemo, so you can be treated promptly. Sometimes, the doses of the drugs may need to be reduced or treatment may need to be delayed or stopped to prevent the effects from getting worse.

Immunotherapy in brain tumor

Immunotherapy provides promising brain cancer treatment options, traditionally treated with chemotherapy, radiation therapy, and surgery. Temozolomide (Temodar®) chemotherapy was approved in 2005 for the treatment of newly diagnosed patients with glioblastoma (GBM) on the basis of a randomized phase III clinical trial showing that it added 2.5 months to the median patient survival. Over 50% of GBM tumors, however, produce a DNA repair protein called MGMT (methylguanine methyltransferase) that effectively neutralizes chemotherapy with temozolomide. These patients derive a negligible therapeutic benefit when temozolomide is added to their therapy.

Immunotherapy is a type of treatment that helps kill cancer cells by taking advantage of a person’s own immune system. For brain and nervous system cancers, there are currently two FDA approved immunotherapy options.

Targeted Antibodies

• Bevacizumab (Avastin®): a monoclonal antibody that targets the VEGF/VEGFR pathway and inhibits tumor blood vessel growth; approved for advanced glioblastoma.
• Dinutuximab (Unituxin®): a monoclonal antibody that targets the GD2 pathway; approved for first-line treatment of high-risk pediatric neuroblastoma.