Brain Tumor: Types, Causes, Symptoms, Diagnosis, and Treatment
A brain tumor is a condition that involves an abnormal multiplication of cells in the brain. Tumors can be cancerous or non-cancerous in nature. Cancerous tumors are often referred to as “malignant,” and non-cancerous tumors are called “benign”. If either kind of tumor grows, they increase the pressure inside the skull, leading to permanent brain damage.
What Is a Brain Tumor?
A brain tumor is a disease characterized by the collection and multiplication of abnormal cells in the brain. Since the skull encloses the brain, any extra growth can cause severe damage.
There are activities constantly going on in our brains; the replacement of old with new continuously takes place. When normal cells grow old or become damaged, new cells take their place. However, in some cases, this process does not happen as it should. The old or damaged cells do not die as per usual, and new cells are made even when the body does not need them. This leads to additional buildup of cells, and these extra cells form a mass of tissue called a tumor, or growth.
Brain tumors are mainly classified into primary and secondary tumors. These tumors can be either benign or malignant in nature. Generally, primary brain tumors are benign and secondary tumors are malignant.
Types of Brain Tumors
Brain tumors are mainly categorized based on their location in the brain. Brain tumors fall under a specific category grade, one through four, based on their behavior, how quickly they grow, and their recurrence after treatment. Benign tumors fall under category grade one or two. They grow slowly and do not return after treatment. Malignant tumors, on the other hand, fall under grades three and four, because they grow rapidly, spread to other parts of the brain, and are likely to recur after treatment.
- Benign tumors: These do not contain any cancerous cells. Benign tumors can be removed and seldom grow back. Benign tumor cells rarely invade the tissues around them. They have an edge or an obvious border around them, so they do not spread to other parts of the body. However, one should not neglect these tumors since they can hit the sensitive part of the brain, which could cause serious health issues and, at times, be life-threatening. There is a chance of benign brain tumors turning malignant.
- Malignant tumors: These are cancer-containing cells. Malignant tumors fall under the serious category and are a threat to one’s life. They do not have a specific border, due to which they grow rapidly, invading the nearby healthy brain tissues. Cancerous cells at times can break away from the malignant tumor and spread to other parts of the brain and even the spinal cord. However, it is rare for these cells to spread to other parts of the body.
Brain tumors are categorized into four different grades based on their attributes:
- Grade I: At the lowest grade, the tissue is benign (non-cancerous). The cells look almost similar to normal brain cells and grow very slowly.
- Grade II: In grade II, the cells look less similar to normal cells and the tissues are considered malignant.
- Grade III: The cells look very different than normal cells and are actively growing. The tissues are also malignant, containing these abnormal-looking cells.
- Grade IV: Under grade IV, the malignant tissues have cells which again look abnormal and tend to grow quickly.
As time passes, the chances of a grade I or II tumor slowly becoming a high-grade tumor (III and IV) increase. Such cases are seen more in adults than in children.
Based on the location, brain tumor types are classified into the following categories:
- Primary brain tumors: These tumors originate in the brain and can develop from brain cells, meningitis, glands, and nerve cells. Mostly found in adults, the common types of brain tumors are oligodendroglioma, meningioma, and astrocytoma. In children, the primary tumors are ependymoma, medulloblastoma, and brain stem glioma. Primary tumors can be benign or cancerous, and mainly fall into one of two types:
- Gliomas: Gliomas are tumors that arise from glial cells. Glial cells support and provide nutrition to the central nervous system; break down dead neurons, and clean cellular waste. The types of tumors that occur in glial cells are:
- Astrocytic: Benign in nature and originate in the cerebrum
- Oligodendroglial: Occur in the temporal frontal lobes
- Glioblastomas: Originate in the supportive brain tissue
- Schwannomas: Originate in the schwann cells
- Meningiomas: Occur in the meninges
Other primary brain tumors include:
- Lymphomas: Malignant in nature
- Primary germ cell tumors: Can be benign or malignant
- Pituitary tumors: Benign in nature
- Craniopharyngiomas: Benign in nature and occur mostly in children
- Pineal gland tumors: Benign or malignant in nature
- Secondary brain tumors: Secondary brain tumors are the most common type of brain tumor. They start in one part of the body and spread to the brain. These tumors begin from another form of cancer and ultimately end in brain tumors. They are also called metastatic brain tumors. The following are the types of cancer from which brain tumors develop:
Who Is at Risk of Developing Brain Tumors?
Brain tumors cannot be controlled. However, there are certain risk factors for developing them. They mainly include:
- Age: As people age, the risk and incidence of brain tumors increase. However, brain tumors can occur at any age.
- Radiation: Those exposed to ionizing radiation are at a greater risk of developing brain tumors. Those exposed to high-dose X-rays and other sources that cause damage to cells have an increased risk of glioma or meningioma.
- Heredity: About ten to fifteen percent of cancers are inherited. Although very rare, some forms of brain tumors can also be inherited.
- Race: The African-American race is at a higher risk of developing meningioma, and brain tumors are commonly seen in Caucasians.
- Chemical exposure: Exposure to certain chemicals and occupational hazards put you at an increased risk of developing brain tumors.
- Chicken pox: Early research suggests that those who have not had chicken pox are at a higher risk of developing brain tumors.
Symptoms of a Brain Tumor
Brain tumor symptoms depend on the size and location of the tumor. Brain tumors increase brain pressure and invade into the brain tissue. The following are some of the common symptoms of a brain tumor:
- Headaches that occur in intervals of sleeping, waking up, while coughing, and during exercise
- Blurred vision
- Vomiting
- Weakness
- Misbalanced mental functioning
- Seizures
- Memory loss
- Vertigo and dizziness
- Loss of bowel and bladder control
- Depression and mood swings
- Muscle weakness
- Reduced ability to hear, smell, and taste
- Decreased alertness
- Difficulty reading and writing
- Hand tremors and uncontrolled movements
- Loss of consciousness
- Tingling sensation in the arms or legs
- Difficulty walking or keeping balance
- Slurred speech
- Sudden changes in personality
How Are Brain Tumors Diagnosed?
Brain tumors are diagnosed in many ways. The tests are mainly based on the patient’s symptoms and medical history. Diagnosis begins with a physical examination, wherein the doctor examines the eyes to check if the cranial nerves are intact, as well as look out for any swelling in the optic nerve. The doctor will evaluate memory loss, coordination, muscle strength, and normal functioning. Other tests include:
- CT scan: Based on the physical examination, the doctor may advise a CT scan, which gives a more detailed picture of the brain using an X-ray machine. It works on the contrast principle by using a special dye that helps doctors visualize the brain more clearly.
- MRI: An MRI scan is similar to a CT scan, the only difference being the MRI doesn’t use radiation. MRI is a large machine linked to a computer that provides detailed pictures of areas inside the head.
- Brain scan: This type of scan involves the use of a harmless radioactive dye, which is injected into the veins. The dye passes through the veins and into the tumor. An image is then captured to visualize the tumor.
- Angiography: Angiography works on the same principle, with dye injected into an artery, usually through the groin. The dye travels through the arteries into the brain, where the tumor can be visualized.
- Biopsy: In this method, a sample of the tumor is taken and passed on to a neuropathology technician. The biopsy can be used to detect if the tumor is benign or malignant. The cells are checked under a microscope for abnormalities. A biopsy is the only sure way to diagnose a brain tumor; it provides details such as what grade it is so treatment can be properly planned.
Treatment of Brain Tumor
Treatment of brain tumors largely depends on the size, location, and type of tumor, as well as the individual’s overall health. The most common treatment is brain tumor surgery. In this, all traces of the tumor are removed without causing damage to other parts of the brain. A benign tumor is removed only if it is clinically dangerous. Surgery is usually accompanied by chemotherapy and radiation therapy.
Speech therapy, physical therapy, and occupational therapy are also recommended after neurosurgery.
Brain tumor surgery: Before surgery, the patient is given anesthesia, and the scalp is shaved. The surgeon then makes an incision in the scalp and uses a special type of saw to remove a piece of bone from the skull. The surgeon will try to remove as much of the tumor as possible. The surgeon will ask you to recite the alphabet and move limbs. This is done to help the surgeon protect important parts of the brain. Once the tumor is removed, the skull is covered with the piece of bone or with a piece of metal or fabric. The incision in the scalp is then closed.
However, surgery is not always the default option, since it becomes difficult if the tumor is present in the brain stem or certain other areas. In such cases, it is hard for the surgeon to remove the tumor without harming the normal brain tissue. Instead of surgery, the individual would receive radiation therapy or chemotherapy.
Radiation therapy: Radiation therapy kills brain tumor cells with high energy from X-rays, protons, or gamma rays. Doctors will use external or internal types of radiation therapy to treat the brain tumors if surgery isn’t the best option.
Chemotherapy: Chemotherapy is the use of drugs to kill the cancer-causing cells. The drugs in chemotherapy are given in various forms, such as by mouth or in the vein (also known as intravenous), and by implanting wafers in the brain.
The doctor will lay out the treatment choices, the outcome of each treatment, and the possible side effects. There are always chances of side effects since cancer therapies often damage the healthy tissues and cells. Work together with your doctor to develop a treatment plan.
Certain questions to ask the doctor before treatment include:
- What is the grade of the tumor?
- Is the tumor benign or malignant?
- What is the type of brain tumor?
- What are the various treatments available for the tumor, and which one is recommended?
- What preparations would one need to make before the treatment?
- What are the risks and side effects, if any, of the treatment?
- What can I expect post-treatment?
Never overlook a brain tumor. Early detection and treatment can prevent serious complications and damage. If you experience the above-mentioned symptoms, consult your doctor right away.
