Brain Tumours

Introduction

About primary brain tumors

A primary brain tumor is a tumor that starts in the brain. A low-grade tumor generally grows slowly, but it can turn into a high-grade tumor. A high-grade tumor is more likely to grow faster.

In adults, secondary brain tumors, also called brain metastases, are much more common than primary tumors.

About secondary brain tumors

A secondary brain tumor is a cancerous tumor that started in another part of the body, such as the breast, lung, or colon, and then spread to the brain. A secondary brain tumor may also be called metastatic cancer or brain metastasis.

Types of Primary Brain Tumors

 

There are many types of primary brain tumors. Some cannot be assigned an exact type because the tumor’s location makes it too difficult to remove for full testing.

Gliomas

As a group, gliomas are one of the most common types of brain tumors. Gliomas may be considered astrocytoma, oligodendroglioma, or ependymoma. Gliomas are assigned a grade, which is an indication of how aggressive a tumor is likely to be. A higher grade is usually more aggressive and more likely to grow quickly.

Currently, the types of gliomas include:

1. Astrocytoma– Astrocytoma is the most common type of glioma.

  •  Grade I or pilocytic astrocytoma is a slowgrowing tumor that is most often benign and rarely spreads into nearby tissue.
  • Grade II or low-grade diffuse astrocytoma is a slow-growing malignant tumor that can often spread into nearby tissue and can become a higher grade. Malignant means it is cancerous and can spread to other parts of the body.
  • Grade III or anaplastic astrocytoma is a cancerous tumor that can quickly grow and spread to nearby tissues.
  • Grade IV or glioblastoma is a very aggressive form of astrocytoma.

2. Oligodendroglioma

3. Ependymoma

4. Brain stem glioma.

Non-glioma tumors

Non-glioma tumors are tumors that arise from cells in the brain that are not glial cells. Types of non-glioma tumors include:

 

  • Meningioma: Meningioma is the most common primary brain tumor. It begins in the meninges and is most often noncancerous.
  • Pineal gland and pituitary gland tumors.
  • Primary CNS lymphoma: This is a form of lymphoma. Lymphoma is a cancer that begins in the lymphatic system.
  • Medulloblastoma: Medulloblastoma is thought to start from a specific type of cell in the cerebellum. It is most common in children and is usually cancerous, often spreading throughout the CNS.
  • Craniopharyngioma.
  • Schwannoma: Schwannoma is a rare tumor that begins in the nerve sheath, or the lining of the nerves.

Risk Factors

Most of the time, the cause of a brain tumor is unknown, but the following factors may raise a person’s risk of developing a brain tumor:

1. Age: Brain tumors are more common in children and older adults, although people of any age can develop a brain tumor.

2. Gender: In general, men are more likely than women to develop a brain tumor.

3. Home and work exposures: Exposure to solvents, pesticides, oil products, rubber, or vinyl chloride may increase the risk of developing a brain tumor.

4. Family history: About 5% of brain tumors may be linked to hereditary genetic factors or conditions.

5. Exposure to infections, viruses: Infection with the EpsteinBarr virus (EBV) increases the risk of CNS lymphoma.

6. Electromagnetic fields: Most studies evaluating the role of electromagnetic fields, such as energy from power lines or from cell phone use, show no link to an increased risk of developing a brain tumor in adults.

7. Ionizing radiation: Previous treatment to the brain or head with ionizing radiation, including x-rays, has been shown to be a risk factor for a brain tumor.

8. Head injury and seizures: Serious head trauma has long been studied for its relationship to brain tumors. Some studies have shown a link between head trauma and meningioma.

9. N-nitroso compounds: These are formed in the body from nitrites or nitrates found in some cured meats, cigarette smoke, and cosmetics.

Symptoms and Signs

Symptoms of a brain tumor can be general or specific. A general symptom is caused by the pressure of the tumor on the brain or spinal cord. Specific symptoms are caused when a specific part of the brain is not working well because of the tumor. General symptoms include:
  • Headaches, which may be severe and worsen with activity or in the early morning
  • People may experience different types of seizures. Motor seizures, also called convulsions, are sudden involuntary movements of a person’s muscles.
  • Personality or memory changes
  • Nausea or vomiting
  • Fatigue
  • Drowsiness
  • Sleep problems
  • Memory problems
  • Changes in ability to walk or perform daily activities
Symptoms that may be specific to the location of the tumor include:
  • Pressure or headache near the tumor.
  • Loss of balance and difficulty with fine motor skills
  • Changes in judgment, including loss of initiative, sluggishness, and muscle weakness or paralysis
  • Partial or complete loss of vision
  • Changes in speech, hearing, memory, or emotional state, such as aggressiveness and problems understanding or retrieving words
  • Altered perception of touch or pressure, arm or leg weakness on 1 side of the body, or confusion with left and right sides of the body
  • Inability to look upward can be caused by a pineal gland tumor.
  • Difficulty swallowing, facial weakness or numbness, or double vision.
  • Vision changes, including loss of part of the vision or double vision

Prognostic factors

To decide on the best treatment for a brain tumor, both the type and grade of the tumor must be determined. There are several factors that help doctors determine the appropriate brain tumor treatment plan and a patient’s prognosis:  
  • Tumor histology: Tumor histology includes finding out the type of tumor, the grade, and additional molecular features that predict how quickly the tumor can grow.
  • Age: In general, a younger adult has a better prognosis.
  • Symptoms: The symptoms a patient has and how long they last may also help determine prognosis. For example, seizures and having symptoms for a long time are linked with a better prognosis.
  • Extent of tumor residual: Resection is surgery to remove a tumor. Residual refers to how much of the tumor remains in the body after surgery. A patient’s prognosis is better when all of the tumor can be surgically removed.
  • Tumor location: A tumor can form in any part of the brain. Some tumor locations cause more damage than others, and some tumors are harder to treat because of their location.
  • Molecular features: Certain genetic mutations found in the tumor may help determine prognosis. These include: IDH1IDH2MGMT, and a 1p/19q co-deletion.
  • Functional neurologic status: A higher score indicates a better functional status. Typically, someone who is better able to walk and care for themselves has a better prognosis.
  • Metastatic spread: A tumor that starts in the brain or spinal cord, even if cancerous, rarely spreads to other parts of the body in adults, but it may grow within the CNS. A tumor that does spread to other parts of the brain or spinal cord is linked with a poorer prognosis.
  • Recurrent tumor: A recurrent tumor is one that has come back after treatment.

Types of Treatment

Treatment options and recommendations depend on several factors:

  • The size, type, and grade of the tumor
  • Whether the tumor is putting pressure on vital parts of the brain
  • If the tumor has spread to other parts of the CNS or body
  • Possible side effects
  • The patient’s preferences and overall health
Treatment options include those described below, such as surgery, radiation therapy, chemotherapy, and targeted therapy. For a low-grade brain tumor, surgery may be the only treatment needed, especially if all of the tumor can be removed. If there is visible tumor remaining after surgery, radiation therapy and chemotherapy may be used. For higher-grade tumors, treatment usually begins with surgery, followed by radiation therapy and chemotherapy.  

Physical, emotional, and social effects of a brain tumor

A brain tumor and its treatment cause physical symptoms and side effects, as well as emotional, social, and financial effects. Managing all of these effects is called palliative care or supportive care. Palliative care focuses on improving how you feel during treatment by managing symptoms and supporting patients and their families with other, non-medical needs. People who receive palliative care along with treatment for the tumor often have less severe symptoms, better quality of life, and report that they are more satisfied with treatment. Some of the symptoms of a brain tumor can be severe and have an enormous impact on the daily lives of patients and their family caregivers. Supportive care for people with a brain tumor includes:
  • These drugs are used to lower swelling in the brain, which can lessen headache pain from the swelling without the need for prescription pain medications.
  • Anti-seizure medicines: These help control seizures, and there are several types of drugs available.

Surgery

Surgery is the removal of the tumor and some surrounding healthy tissue during an operation. It is usually the first treatment used for a brain tumor. Surgery to the brain requires the removal of part of the skull, a procedure called a craniotomy. After the surgeon removes the tumor, the patient’s own bone will be used to cover the opening in the skull. There have been rapid advances in surgery for brain tumors, including the use of cortical mapping, enhanced imaging, and fluorescent dyes. In addition to removing or reducing the size of the brain tumor, surgery can provide a tissue sample for an analysis using a biopsy. For some tumor types, the results of the biopsy can help determine if cancer medications or radiation therapy will be useful. Sometimes, surgery cannot be performed because the tumor is located in a place the surgeon cannot reach or it is near a vital structure. These tumors are called inoperable or unresectable.

 

Radiation therapy

Doctors may use radiation therapy to slow or stop the growth of a brain tumor. It is typically given after surgery and possibly along with chemotherapy. A radiation therapy regimen, or schedule, usually consists of a specific number of treatments given over a set period of time. External-beam radiation therapy can be directed at a brain tumor in the following ways:
  • Conventional radiation therapy: The treatment location is determined based on anatomic landmarks and x-rays. In certain situations, such as whole-brain radiation therapy for brain metastases, this technique is appropriate.
  • 3-dimensional conformal radiation therapy (3D-CRT): Using images from CT and MRI scans, a 3-dimensional model of the tumor and healthy tissue surrounding the tumor is created on a computer.
  • Intensity modulated radiation therapy (IMRT): IMRT is a type of 3D-CRT that can more directly target a tumor. It can deliver higher doses of radiation to the tumor while giving less to the surrounding healthy tissue. In IMRT, the radiation beams are broken up into smaller beams and the intensity of each of these smaller beams can be changed.
  • Proton therapy: Proton therapy is a type of external-beam radiation therapy that uses protons rather than x-rays. It is typically used for tumors when less radiation is needed because of the location.
  • Stereotactic radiosurgery: Stereotactic radiosurgery is the use of a single, high dose of radiation given directly to the tumor and not healthy tissue.
  • Fractionated stereotactic radiation therapy: Radiation therapy is delivered with stereotactic precision but divided into small daily doses called fractions and given over several days or weeks, in contrast to the 1-day radiosurgery.
Short-term side effects from radiation therapy may include fatigue, mild skin reactions, hair loss, upset stomach, and neurologic symptoms, such as memory problems. Most side effects go away soon after treatment is finished. Longer term side effects of radiation therapy depend on how much healthy tissue received radiation and include memory and hormonal problems and cognitive (thought process) changes, such as difficulty understanding and performing complex tasks.

Therapies using medication

Treatments using medication are used to destroy cancer cells. Medication may be given through the bloodstream to reach cancer cells throughout the body. When a drug is given this way, it is called systemic therapy. The types of medications used for a brain tumor include:
  • Chemotherapy
  • Targeted therapy

Chemotherapy

Chemotherapy is the use of drugs to destroy tumor cells, usually by keeping the tumor cells from growing, dividing, and making more cells. Some drugs are better at going through the blood-brain barrier. These are the drugs often used for a brain tumor.
  • Gliadel wafers are a way to give the drug carmustine (BiCNU). These wafers are placed in the area where the tumor was removed during surgery.
  • For people with glioblastoma and high-grade glioma, the latest standard of care is radiation therapy with daily low-dose temozolomide. This is followed by monthly doses of temozolomide after radiation therapy for 6 months to 1 year.
  • A combination of 3 drugs, lomustine , procarbazine, and vincristine has been used along with radiation therapy.
Patients are monitored with a brain MRI every 2 to 3 months while receiving active treatment. Then, the length of time between MRI scans increases depending on the tumor’s grade. The side effects of chemotherapy depend on the individual and the dose used, but they can include fatigue, risk of infection, nausea and vomiting, hair loss, loss of appetite, and diarrhea. These side effects usually go away after treatment is finished. Others may cause kidney damage. Patients may be given extra fluid by IV to protect their kidneys.

Targeted therapy

Targeted therapy is a treatment that targets the tumor’s specific genes, proteins, or the tissue environment that contributes to a tumor’s growth and survival. Not all tumors have the same targets, and some tumors may have more than 1 target. A variety of targeted therapies are being studied in brain tumors that contain other specific molecular changes;  

Alternating electric field therapy (tumor treating fields)

This type of treatment uses a non-invasive portable device that interferes with the parts of a cell that are needed for tumor cells to grow and spread. It is given by placing electrodes that produce an electric field on the outside of a person’s head. Alternating electrical field therapy may be an option for people newly diagnosed with glioblastoma or for those with recurrent glioblastoma. Researchers have found that people with recurrent glioblastoma who used the device lived as long as those who received chemotherapy. In addition, they had fewer side effects.

Remission and the chance of recurrence

A remission is when the tumor cannot be detected in the body. A remission can be temporary or permanent. For most primary brain tumors, despite imaging tests showing that the tumor growth is controlled or there are no visible signs of a tumor, it is common for a brain tumor to recur. Patients will often continue to receive regular MRI scans to watch for a recurrence. This uncertainty causes many people to worry that the tumor will come back. When this occurs, a new cycle of testing will begin again to learn as much as possible about the recurrence. Often the treatment plan will include the treatments described above such as surgery, radiation therapy, chemotherapy, and targeted therapy, but they may be used in a different combination or given at a different pace. Options may include:
  • Temozolomide
  • Bevacizumab
  • Alternating electric field therapy for people with recurrent high-grade glioma
  • Clinical trials studying new treatments

Metastatic cancer

If cancer spreads from where it started to another part of the body, doctors call it metastatic cancer. If this happens, it is a good idea to talk with doctors who have experience in treating it. Your treatment plan may include a combination of surgery, radiation therapy, targeted therapy, and immunotherapy, which is a type of treatment designed to boost the body’s natural defenses to fight the tumor.

Treatment of brain metastases

If cancer spreads to the brain from another part of the body, it is called a brain metastasis, metastatic cancer, or a secondary brain tumor. Brain metastases have traditionally been treated with surgery or radiation therapy. Chemotherapy is not often used because the blood-brain barrier keeps many drugs from reaching the brain. However, other medications like targeted therapy and immunotherapy are options for certain people. Current options for treating brain metastases include:
  • Surgery: Surgery is generally only an option for patients who have one or two areas of cancer in the brain, especially when the tumors are large and causing symptoms.
  • Radiation therapy: For people with 1 to 4 tumors, high-dose radiation therapy given using stereotactic techniques (see “Radiation therapy,” above) is preferred. Stereotactic radiosurgery focuses the radiation only on the tumor in the brain, and this can also help lessen the side effects.Whole-brain radiation therapy is radiation therapy given to the entire brain, and it may be an option for some people.
  • Targeted therapy: Some types of targeted therapy can enter the brain tumors and are able to target specific genetic changes in cancer that reaches the brain from metastatic disease that began elsewhere.
  • Immunotherapy: Some types of immunotherapy have shown promise in treating brain metastases from lung cancer and melanoma. Immunotherapy is another type of therapy using medication.
  Below is a general summary of when and how surgery and radiation therapy are used to treat brain metastases:
  • People with 1 to 3 brain metastases generally receive stereotactic radiosurgery. If the brain metastases are large or causing symptoms due to pressure on the brain and the person is in general good health, they often receive surgery, followed by stereotactic radiosurgery.
  • Treatment for people in relatively good health and with more than 4 tumors that cannot be removed with surgery or more than 2 tumors that were removed surgically may include stereotactic radiosurgery or whole brain radiation therapy.
  • People who also have metastatic cancer in parts of the body other than the brain usually continue their treatment regimen if the disease outside the brain is not worsening.

Treatment of leptomeningeal metastases

If cancer spreads to the meninges or the CSF, it is called leptomeningeal metastases. People with leptomeningeal metastases may receive chemotherapy given directly into the CSF of the brain. This may be done with a lumbar puncture and is called intrathecal chemotherapy. Radiation therapy may also be an option.

Managing the symptoms and side effects of brain metastases

The symptoms of brain metastases depend on where in the brain the cancer has spread, how much cancer is in the brain, and how quickly it spreads. Relieving a person’s symptoms and side effects is an important part of cancer care. Treatment for symptoms can continue even when active treatment to cure or slow down the cancer stops. The following options to help relieve symptoms of brain metastases:
  • Dexamethasone (available as a generic drug), a type of drug called a corticosteroid, to lower swelling in the brain and help improve neurological symptoms caused by the tumor and swelling in the healthy brain tissue.
  • Anti-seizure medications are only recommended for people who are having seizures.