Brain Tumor

Brain tumors are rare in Hong Kong. Statistics from The Hong Kong Neurosurgical Society show that there were around 1,000 new cases of brain tumor in 2009, of which 70 were malignant gliomas and 200 were secondary brain tumors. However, primary brain tumors are more common among people aged 0-19 in Hong Kong. Of all the new cancer cases in children and adolescents (0-19 years) in 2006, primary brain tumor ranked fifth in males and fourth in females.

Brain tumor is not incurable. As new treatments continue to be developed, if brain tumor is detected and treated early, the chances of recovery are high.

(Special thanks to Dr. K N HUNG, Chief of Service, Department of Neurosurgery, Queen Mary Hospital for reviewing the information of this page.)

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The brain has three main parts, the cerebrum, the cerebellum and the brain stem.  The cerebrum is the commander of the human body. It is divided into two hemispheres. Each hemisphere contains four lobes, the frontal lobe, parietal lobe, temporal lobe and occipital lobe, which control specific functions of the body.

A brain tumor is an abnormal growth of cells within the brain. It can be malignant or benign. Malignant tumors are cancers. Benign tumors are relatively slow growing.  They don’t spread to other parts of your body. Malignant tumors are relatively fast growing and may invade or press on surrounding tissue, affecting the function of the brain and can be life threatening.

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Brain tumors can be primary or secondary.

Primary brain tumors
Primary brain tumors originate in the brain. They are abnormal and uncontrolled growth of cells in the brain. They can be either benign or malignant. Brain tumors are generally named after the type of brain cells that they contain. The most common type of primary brain tumor is a glioma. For example, astrocytoma is the tumor arises from star-shaped glial cells.

Secondary brain tumors
Secondary brain tumors are tumors that have spread to the brain from cancers in other parts of the body. Some of these cancers locate near the brain. Nasopharyngeal cancer is a typical example.

Other secondary brain tumors are formed by cancerous cells from the primary tumors that have travelled in the bloodstream and lodged in the brain. For example, from tumors that originally started in the lung or breast. These secondary brain tumors may be detected a long time after the primary tumors being treated. 15% of the patients have no history of cancer or tumor.

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Doctors are not sure what causes brain tumors. Only a few cases indicated that they might be inherited or caused by chemicals. Hence, there is no known way to prevent it.  Some scientists say that the radiation of mobile phones may be a factor. However, there is no evidence to prove it yet.
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The cause of brain tumors is still unknown. However, there are a number of factors that may increase the risk of developing a brain tumor. They include:

  • Age:  Brain tumors may occur at any age, but they are more common in people over 40 years old. Certain types of brain tumors, such as medulloblastomas, occur almost exclusively in children.
  • Sex:  Brain tumors are more common in men than women.
  • Family history:  People with family members who have gliomas may be more likely to develop this disease.
  • Exposure to radiation or to certain chemicals at work, such as formaldehyde, vinyl chloride and acrylonitrile.
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相片 The symptoms of brain tumors depend on tumor location, type and size. Some people may have no symptoms at all and their tumors are discovered by chance in physical examination. Anyone with several of the following symptoms should see a doctor as soon as possible:

  • Seizures
  • Headaches
  • Nausea or vomiting
  • Gradual loss of sensation or movement in arms or legs, numbness, partial paralysis, problems in balancing or walking
  • Confusion, personality changes or memory loss
  • Tinnitus, dizziness
  • Numbness or tingling of facial muscles
  • Difficulty swallowing
  • Decreased vision or double vision
  • Endocrinal disorders
  • Speech problems, difficulties in both language comprehension and expression
  • Bladder and bowel problems
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Doctors may perform a number of tests and procedures, such as clinical tests, CT scan, MRI, PET, blood vessel imaging, spectrum scan, or biopsy to diagnose brain tumors. The following are some of the common tests and procedures:

 

CT scan (Computerized Tomography scan) 

It uses X-rays to make a three-dimensional picture of the brain to show the position and condition of  the tumor. A dye may be injected into a vein to help showing it more clearly

MRI scan (Magnetic Resonance Imaging scan)

It uses magnets and radio waves to produce images of the brain. With a 90% accuracy rate, it helps in guiding surgical treatment and radiotherapy. It is particularly effective for diagnosing astrocytoma and posterior cranial fossa tumors, especially brain stem tumor.

PET scan (Positron Emission Tomography scan)
It is a type of imaging test that can detect cancerous cells precisely. It involves injecting a small amount of radioactive substance (a tracer) into the vein. The tracer travels through the body to detect the disease. It is best for people with secondary tumors to trace the location of the primary tumors.

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Treatments can involve surgery, radiation therapy and chemotherapy. Doctors will tailor treatment to fit individual situation. If the patient’s condition is not severe, the chance for cure is high and the risk of surgery is low, the doctor will work for complete surgical removal. Some patients have to receive supplementary medications or radiotherapy for a period of time after surgery to prevent from recurrence.

Treatment options include:

Surgery
Surgery is the primary form of treatment for tumors. The doctor will open the skull of the patient and remove as much of the brain tumor as possible. In some cases, tumors are located near sensitive areas in the brain, making surgery risky. In these cases the doctor may try to remove as much of the tumor as is safe. The remaining portions will be removed by radiation therapy or chemotherapy.

As minimally invasive surgery techniques are increasingly refined, surgeons are able to remove the tumors more effectively and safely, while the scope for removing the tumors is expanded. It also increases the chances of recovery and reduces the side effects.

Radiation therapy
Radiation therapy uses high-energy rays to kill tumor cells and reduce the damage to the surrounding healthy cells. In recent years, doctors have used more advanced radiation therapies, such as intensity modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT) and volumetric modulated arc therapy (VMAT). They can increase the dose of radiation to kill the tumor cells and spare normal tissues.

Radiation therapy usually follows surgery. In some cases, it is used along with chemotherapy. The immediate risks of radiation therapy are lower than that of surgery.  Still, there are complications such as hydrocephalus, hair loss, headache, nausea, vomiting, and skin may become red and sore.

Chemotherapy
Chemotherapy uses drugs to kill cancer cells. Common drugs include Temozolmide or Carmustine, BCNU. Chemotherapy drugs can be taken orally or injected into a vein so that they enter the bloodstream and travel throughout the body to destroy cancer cells. However, they can also damage healthy cells and may cause side effects such as vomiting, dizziness, hair loss, fatigue and infection.

Another type of chemotherapy can be placed during surgery. The surgeon removes the tumor and place several wafers in the void left by the tumor. They directly release the chemotherapy drug into the brain which kills cancer cells. It can reduce the chance of spreading the drugs to other areas and thus cause damage to the healthy cells.

Targeted drug therapy
It is a comparatively new therapy. Targeted drug treatments focus on specific abnormalities present within cancer cells. Drugs are given through a vein to stop the formation of blood vessels, cutting off blood supply to a tumor and cause cancer cells to die. Many targeted drug therapies are very new and still undergoing study in clinical trials.

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The brain is a vital organ. Complications of brain tumors may bring devastating effects or permanent damages that lead to physical disabilities, coma or even the patient’s death.

Here are some of the complications to bear in mind:

  • Weak cognitive and logic abilities, memory loss
  • Problems in vision, hearing, smell or speech due to nerves damage
  • Coma
  • Stroke, weak in arms and legs, paraplegia
  • Hormonal disorders, cerebrospinal fluid leak
  • Seizures
  • Meningitis
  • Infection
  • Bladder and bowel problems
  • Pneumonia
  • Personality changes
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Patients should learn more about the disorder, treatment options and things to note after surgery, so that they will have enough confidence to cope with the disease and won’t be too panic. They should also talk to family members about their conditions frankly. Discuss with them about treatments and all sorts of arrangements. Obtaining emotional support from family members is very helpful.

After going home from the hospital, they should see the doctors regularly. Let the doctors check them closely, treat their complications, detect recurrence of the illness and apply adequate treatments.
 
The tumors or therapies may cause damage to the brain and neurological functions that impair hearing, vision or motor skills. Hence, patients may have to receive physical therapy, speech therapy or occupational therapy, etc. Through a series of rehabilitation training, recovery of the impaired functions to a certain extent is possible.

Here are some suggestions for self-care:

  • Maintain a balanced diet. Eat less stimulating foods
  • Quit smoking and alcohol
  • Regular exercise
  • Learn to relax and reduce stress, e.g. listening to music
  • Be happy and optimistic
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