A brain tumor is a growth or mass of abnormal cells in the brain. There are many different types of brain tumors. Some are noncancerous (benign), and some are cancerous (malignant). Brain tumors can start in the brain (primary brain tumors), or cancer can form in other parts of the body and spread to the brain (secondary, or metastatic, brain tumors). Cancer of the colon, lung, breast and kidney usually metastasize to the brain.
The growth rate as well as the location of a brain tumor determines how it will impact the function of the nervous system. Its treatment options will vary accordingly.
According to doctors, every year 40,000-50,000 persons are diagnosed with brain tumor in India. Of these, 20 per cent are children. Brain tumor is also the second most common cancer among children after leukaemia.
Types of brain cancer
Cancer is named based on where in the body it forms. Cancerous tumors in the brain are generally metastatic and not due to primary brain cancer.
There are also grades and types of brain tumors. The tumor type is based on where it is located in the brain, and the grade indicates how quickly a tumor grows. The grades range from 1 to 4. Grade 4 has the fastest growth.
It is important to note that there are more than 120 types of brain tumors. However, there is no standard for naming them according to type, and there are many subtypes. Different surgeons might use different names for the same tumor. Some of the most common types are:
- Astrocytomas – These mostly form in the largest part of the brain – the cerebrum. They can be any grade. They often cause changes in behavior or seizures.
- Meningiomas – These are the most common primary brain tumors. They are likely to occur in the 70s or 80s. They begin in the meninges, the lining of the brain. They can be grade 1, 2, or 3. They are mostly benign and grow slowly.
- Oligodendrogliomas – These form in the cells that make the covering that protects the nerves. They are mostly grade 1, 2, or 3. They usually grow slowly and don’t spread to nearby the tissue.
Although there are a few warning signs, the most common symptoms of brain cancer may include:
- Difficulty in walking and/ or vertigo/dizziness
- Headaches (persistent and/ or severe)
- Muscle weakness (for example, leg and arm weakness)
Other common symptoms that can occur are:
- Blurry vision
- A change in a person’s alertness
- Memory problems
- Mental capacity reduction and or confusion
- Changes in speech, such as impaired voice, difficulty in speaking, or inability to speak
- Weakness on one side of the body
- Coordination problems
- Pins and needles sensations and/ or reduced sensation of touch
Causes and diagnosis
As with tumors elsewhere in the body, the exact cause of brain cancer is unknown. Various environmental toxins, genetic factors, HIV infection, radiation to the head, and cigarette smoking have all been linked to cancers of the brain. In most of the cases, no clear cause can be proved.
In most cases, a CT scan is used to diagnose brain cancer. The test is similar to an x-ray, but shows more detail in three dimensions. A contrast dye is injected into the bloodstream to highlight abnormalities on the scan.
However, now the MRI scan is being used instead of a CT scan for suspected brain cancer. The reason is MRI has a higher sensitivity for detecting the presence of, or changes within, a tumor.
The next step in diagnosis is confirmation that you have brain cancer, usually by taking and testing a sample of the tumor. This procedure is called a biopsy:
- The most widely used technique is surgery. The skull is opened, mostly with the intention of removing the whole tumor. A biopsy is then taken from the tumor.
- If the doctor is unable to remove the entire tumor, a small piece of the tumor is removed.
- In few cases, it is possible to collect a biopsy without opening the skull. The exact location of the tumor in the brain is determined by using a MRI or CT scan. A small hole is then made in the skull and a needle is guided through the hole to the tumor. The needle collects the biopsy and is removed. The technique is called stereotactic biopsy, or stereotaxis.
- The biopsy is examined under a microscope by a pathologist.
Grades and treatment options
While other cancers are usually classified by stages, brain cancer is assigned a ‘grade’ based on its pathologic features or how the cells look under a microscope. It is described as the following:
- Grade I – The tumors are noncancerous or slow-growing, and the cells look almost similar to healthy cells.
- Grade II – The tumors are cancerous yet slow-growing, and the cells look a little abnormal when viewed under a microscope. The tumors may spread to the nearby tissues, or they may return after the initial treatment.
- Grade III – The tumors are cancerous and grow faster than grade I and II tumors. The cancerous cells have significant abnormalities that show up during a microscopic analysis, and they actively reproduce abnormal cells that may spread elsewhere in the brain.
- Grade IV – The tumors are fast-growing and have a number of abnormal characteristics that are quite apparent when the cells are viewed under a microscope. The tumors often quickly spread to the other parts of the brain, and may even produce their own blood vessels to support the growth. Sometimes they also have small clusters of dead cells (necrosis) in their core.
Although other cancers usually do not change stages, brain tumor can progress to a more advanced grade over time. It is also worth noticing that any other cancer that spreads to the brain is considered stage IV, irrespective of the characteristics of the original tumor.
Treatment options for a brain tumor depends on the size, type, and location of the tumor, as well as the overall health and personal preferences:
- Surgery – In case the tumor is located in a place that makes it accessible for an operation, the doctor will aim to remove as much of the brain tumor as possible.
- Minimally invasive scarless brain surgery – The procedure is used to help people who have been told they have an inoperable brain tumor (these are unable to be removed surgically due to their location in the brain or because of multiple tumors). The surgical team is able to remove the tumor safely with minimized risk of complications.
- Radiation therapy – This procedure uses high-energy beams like protons and x-rays to kills tumor cells.
- Radiosurgery – This procedure uses multiple beams of radiation to give a highly focused form of radiation treatment to destroy the tumor cells in a very tiny area. Each beam of radiation is not particularly powerful, however the point where all the beams meet — at the brain tumor — receives a very large dose of radiation to destroy the tumor cells.
- Chemotherapy – It uses drugs to kill tumor cells. The drugs can be injected into a vein (intravenously) or taken orally in a pill form.
- Targeted drug therapy – This treatment focuses on specific abnormalities present within the cancer cells. By blocking these abnormalities, the treatment can cause the cancer cells to die.
Side effects of treatment
Brain tumors can cause effects that can have an impact on the quality of life. They can affect parts of the brain which control many different functions. Some of the side effects may include:
- Memory difficulties
- Personality changes
- Cognition (thinking skills)
- Communication difficulties
- Sight problems
- Learning difficulties
Survivorship and prevention of brain cancer
Because brain tumors can form in parts of the brain that control speech, motor skills, thinking and vision, rehabilitation may be a necessary part of recovery and survivorship. Depending on your needs, the doctor may refer you to:
- Occupational therapy to help you get back to the normal daily activities, including work, after a brain tumor or other disease.
- Physical therapy to help you regain lost muscle strength or motor skills.
- Speech therapy with specialists in speech difficulties to help if you have difficulty speaking.
- Tutoring for school-age children to help children cope with changes in their thinking and memory after a brain tumor.
- Home hospice care is another way of providing symptom and pain relief, as well as emotional and physical support for the patient and the family, at home rather than in the hospital. It usually involves a multidisciplinary approach that may include a doctor, nurses, aides, a pharmacist, counselors, a social worker, and a spiritual caregiver.
There is no definite way to prevent brain cancer, but you can reduce the risk of getting it if you:
- Avoid exposure to carcinogenic chemicals
- Avoid exposure to insecticides and pesticides
- Avoid smoking
- Avoid unnecessary exposure to radiation
Always remember your long-term outlook depends on the size, type, and location of the brain tumor. Brain cancer usually has a low survival rate. Few brain cancer treatments can increase the risk of getting other cancerous tumors or may cause cataracts, which means clouding of the eyes. So remember to stay healthy, stay safe!