A brain tumor is an abnormal growth of atypical tumors cells in the brain or structures close to the brain. There are multiple different types of brain tumors. Some brain tumors are benign (noncancerous), and some brain tumors are malignant (cancerous). Brain tumors can develop in a brain (primary brain tumors), or cancer can begin in other parts of the body and spread to the brain with blood flow or other ways (secondary, or metastatic, brain tumors). The speed of tumor growth can be varied. The growth rate, as well as location of a brain tumor, determines main clinical symptoms and affected functions of the nervous system. Malignant primary brain tumors (oncological processes that begin in the brain), typically grow faster and more aggressively invade surrounding tissue than benign tumors. Despite the fact that brain tumor rarely spreads to other organs, it more likely spread to other sections of the brain and central nervous system. Brain tumor treatment opportunities and options depend on the histological type of brain tumor, as well as its size and location.
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What is Brain Tumors?
Primary Brain Tumors. They arise in the brain or tissues close to it, such as the meninges (brain-covering membranes), cranial nerves, pituitary gland or pineal gland. They occur when normal cells obtain mutations in their DNA. These changes cause non-controlled growth and dividing with a loss of their primary functions. Primary brain tumors are much rarer than are secondary brain tumors, which begins in other organs and then spreads to the brain. Classification of primary brain tumors based on the type of cells involved. For example:
- These tumors involve glial tissue (which provides support and protection for neurons) and can occur in the brain or spinal cord. They include glioblastomas, ependymoma, astrocytomas, oligoastrocytomas, and oligodendrogliomas.
- A meningioma involves the membranes that surround the brain and spinal cord (meninges). Most meningiomas are benign. However, they can press essential structures or nerves causing severe neurologic symptoms.
- Acoustic neuromas. These benign tumors involve the nerves that regulate balance and hearing.
- Pituitary adenomas. These are often benign tumors of pituitary gland at the base of the brain. They can change the pituitary hormones secretion with severe general effects in all body.
- These are the common malignant brain tumors in children.
- Primitive neuroectodermal tumors (PNETs) are very rare, malignant neoplasm that originates from embryonic cells in the brain. Germ cell tumors. This type of tumors may develop in children during the testicles or ovaries formation. However, germ cell tumors can spread to other organs, such as the brain.
- These rare, benign tumors develop near the pituitary gland.
Neoplasms that begins in other organs and spreads to the brain. Secondary brain tumors mostly occur in individuals who have a history of cancer. However, in some cases, a metastatic brain tumor may be the first sign of cancer that began in another organ. Secondary brain tumors are considerably more widespread than are primary brain tumors. Any malignant neoplasm can spread to the brain, but the most common types include:
- Breast cancer
- Colon cancer
- Kidney cancer
- Lung cancer
The main symptoms, then, that might indicate the development of a brain tumor include:
• Headaches that appear primarily at night and early in the morning and dissipate over the course of the day. (The headaches can be so severe as to wake them up from sleep.)
• Headaches are worse upon exertion, and when sneezing or coughing
• The child tends to tilt their head to the side
• Prolonged pain in the nape of the neck
• Vomiting in the mornings
• Fatigue and extreme exhaustion
• Behavioral changes (e.g. apathy)
The symptoms of a brain tumor can significantly vary and depend on the location, size, and rate of growth and malignancy of the tumor. Manifestation of brain tumors may include:
- Severe headaches without other explanations
- Unexplained nausea or vomiting
- Eyesight problems (loss of peripheral vision, blurred vision or double vision)
- Progressive loss of sensation or movement in extremities
- Hearing disorders
- Balance disorders
- Speech problems
- Changes in personality or behavior
Seizures, or any symptoms of epilepsy (especially without a history of seizures)
In the case of suspect the brain tumor, physician may prescribe some diagnostic procedures and tests, which may include:
A full neurological examination. A neurological examination usually includes checking of all reflexes and their symmetry, presence of pathological reflexes, as well as diagnostic measures of vision, hearing, balance, coordination and strength. Changes in one or more areas may provide important signs about the certain brain part that could be affected by a tumor.
Imaging diagnostic methods. Magnetic resonance imaging (MRI) is ordinarily used to diagnose brain tumors. In some cases, the contrast (a special dye for better visualization of some tissues and organs) may be injected into arm vein during MRI study.
Various specialized MRI scan tools such as functional MRI, perfusion MRI, and magnetic resonance spectroscopy, may be helpful in come cases to evaluate the tumor and to choose a treatment plan. Diagnostic process may involve other imaging methods such as computerized tomography (CT) and positron emission tomography (PET).
Diagnostic methods for finding tumor cells in other parts of the body. If it’s suspected that brain tumor may be secondary regarding an oncological process that has spread from another organ, an oncologist may prescribe tests and procedures to determine where cancer began.
Biopsy and histological study (including immunohistochemical study) of the sample of abnormal tissue. A biopsy can be performed during an operation aimed to remove the brain tumor, or a biopsy can be carried out using the special needle.
A stereotactic needle biopsy may be done for brain tumors in difficult to reach or very sensitive brain regions that can be injured by a more extensive surgery. Neurosurgeon drills a small hole into the skull. A thin needle is then injected through the hole. The tumor tissue is extracted using the needle, which is usually guided by CT or MRI scanning. The tissues samples are then viewed under a microscope during the histological study to determine if it is malignant or benign. This information is crucial to confirm a diagnosis and prognosis and, most importantly, in choosing of treatment method.
Treatment of brain tumors depends on the type, size, and location of the tumor and may include surgery, radiation therapy (as well as radiosurgery), chemotherapy and in some cases – targeted drug therapy.
If the tumor is located in an accessible for an operation place, neurosurgeons discuss and decide the possibility of the operation to remove as much of the tumor tissue as possible.
In some cases, tumors are small and accessible to separate from surrounding brain tissue, allowing complete surgical removal of a tumor. Moreover, it is a very positive prognostic factor. In other cases, tumors cannot be completely separated from surrounding tissue or they are located near critical and sensitive zones in the brain, making surgery riskier. In these situations, a neurosurgeon removes as much of the tumor as is safe for further life and normal brain functions. Even removing of a part of the brain tumor may significantly reduce symptoms and increase life quality.
Removing of a brain tumor carries risks, such as infection and bleeding. Other hazards may depend on the part of the brain where a tumor is located. For example, surgery on a tumor near nerves that connect to eyes has a risk of vision loss.
This method uses high-energy radiation, (for example, X-rays, protons) to destroy tumor cells. Radiation therapy can be performed by special apparatus outside the body (external beam radiation), or source of radiation can be installed inside the brain close to a tumor. This method usually called like brachytherapy.
External beam radiation can direct just on the affected area of the brain where the tumor is located, or it can be applied to the whole brain. Whole-brain radiation is most often used to treat secondary brain cancer that has spread from another part of the body.
Side effects depend on the type and dose of radiation which is received. Common side effects during or immediately following radiation may include headaches, fatigue, and scalp skin irritation.
Stereotactic radiosurgery is not a type of surgery in common sense. Rather, radiosurgery employs high-energy beams to provide a highly focused form of radiation treatment to destroy the tumor cells in a very small brain section. By this method, tumor receives a large dose of radiation to destroy the tumor cells and at the same time to cause fewer side effects for all organism. There are various types of technology employed in radiosurgery to deliver radiation to brain tumors, some of them are “Gamma Knife” or “linear accelerator” (LINAC).
During chemotherapy, patients receive drugs to destroy tumor cells or to stop their growth. Chemotherapy medications can be taken orally in pill form or injected into a vein (intravenously). There are different pharmacological groups of chemotherapy drugs, which are prescribed depending on tumor types. Chemotherapy side effects may include nausea, vomiting, hair loss. They depend on the type and dose of received drugs. Usually, physicians use special pharmacotherapy to reduce side effects of chemotherapy.
Targeted drug therapy
As medical science has studied more about the inner molecular mechanisms of cells that can cause cancer or take part in cancer cells grow, oncologists have developed newer drugs that specifically target these mechanisms. These targeted drug molecules act differently from standard chemotherapy medications. In some cases, they work when chemotherapy drugs do not, and they often have different (and less severe) side effects. These drugs do not yet play a significant role in treating of brain tumors, however, some of them may be helpful for certain histological types of tumors.
Rehabilitation after treatment
As brain tumors can occur in parts of the brain that regulate motor skills, speech, vision and thinking, rehabilitation process may be fundamental relearning how to compensate this problem and to carry out their needs. The rehabilitation must involve work with the motor skills of persons with disabilities after the brain tumor treatment, as well as attitudes of the patients and their family and friends. It develops their domestic skills to achieve the highest level of independence possible for them. Besides, rehabilitation may give psychological support to encourage patients to rebuild self-esteem and a positive mood allowing successful community reintegration.