Brain cancer or tumor is an abnormal growth of cells in the brain. Cancer (malignant) cells are a bunch of cancer tissue that obstruct with many brain functions including sensation, memory, muscle coordination and other normal functions of the body. Tumours which comprise of cancer cells are called malignant tumors, and those which comprise mainly of noncancerous cells are known as benign tumors. Cancer cells that originate from brain tissue are called primary brain tumours while tumours that spread from other body parts to the brain are called metastatic or secondary brain tumors. Growth rate of brain tumor vary significantly. How quickly the tumor grows as well as where it is located in the brain decides how it will affect the functions of nervous system.
The treatment of brain cancer depends on the type of brain tumor, its site and growth.
Symptoms of brain tumor
The signs and symptoms of a brain tumor depend on tumor's size, location and rate of growth.
Common signs and symptoms caused by brain tumors may include:
Causes and types of brain tumor
1. Primary brain tumor
The cancers which originate in the brain itself or in its nearby tissues could be in the brain-covering membranes, pituitary gland, pineal gland and cranial nerves. Primary brain tumors begin when normal cells undergo some mutations at genetic level, such as mutation in their DNA. These mutations lead the cells to grow and divide at a very fast rate and to continue living when healthy cells would die. This result in the formation of lump of abnormal cells, which turns to be a tumor. In elderly people, primary brain tumors are much less common than the secondary brain tumours.
There are variety of primary brain tumours. Each type of primary brain tumor gets its name from the cell type it involves. Examples include:
a) Gliomas - These tumours start in the brain or spinal cord and include astrocytomas, ependymomas, glioblastomas, oligoastrocytomas and oligodendrogliomas.
b) Meningiomas - A meningioma is a tumor that develops from the membranes of the brain and spinal cord (known as meninges). Most of the meningiomas are noncancerous.
c) Acoustic neuromas (schwannomas) - Benign tumors that emerge on the nerves that control balance and hearing. The cancer leads from the inner ear to the brain.
d) Pituitary adenoma - Tumours that develop in the pituitary gland at the base of the brain and mostly benign. These tumors can affect the hormones secreted by pituitary gland.
e) Medulloblastomas - The most cancerous brain tumors seen in children. A medulloblastoma first starts in the lower back part of the brain and then spread through the spinal fluid. These types of tumors are rare in adults.
f) Germ cell tumours - Germ cell tumours may be experienced during childhood in the genital area where the testicles or ovaries formation takes place. Sometimes germ cell tumors can affect other parts of the body, including the brain.
g) Craniopharyngiomas - These are rare, noncancerous tumors start near the pituitary gland. It is a slow-growing tumor and can affect the pituitary gland and other structures nearby brain.
2. Secondary (metastatic) brain tumor
Cancer that originates from somewhere else and reaches the brain is known as metastatic or secondary brain tumor. Secondary brain tumors most often found in individuals with a family history of cancer. In adults, secondary brain tumors are more common than are primary brain tumors. Any type of cancer can spreads to the brain, but common types include breast, kidney, lungs and colon cancer.
In most patients with primary brain tumors, the cause of the tumor is not understandable. But researchers have identified some triggers and factors that may increase developing a tumor in brain. These factors include:
Radiation exposure - People who have been exposed to an ionizing radiation have a greater risk of brain tumor. Radiation therapy used as cancer treatment and exposure caused by atomic bombs are common examples of ionization radiation.
Family history of brain tumours - A possibility that family history of brain tumors or a family history of genetic syndromes can increase the risk of brain tumor.
Other risk factors may include smoking and growing age.
If brain cancer is suspected in an individual, the doctor may recommend a series of tests and screening protocols, including:
a) A neurological examination - A neurological exam may include assessment of vision, hearing, balance, coordination, strength and reflexes. Problem in one or more areas may be an indication about the part of the brain that could be affected by a brain tumor.
b) Magnetic resonance imaging (MRI) - MRI is the most common imaging tool used to diagnose brain tumors. In some protocols of MRI, a dye may be injected through a vein before going for the scan. This is known as contrast MRI. Contrast MRI is used to obtain more detailed images. A number of specialized MRI scan such as functional MRI, perfusion MRI and magnetic resonance spectroscopy may help doctor to evaluate tumor.
c) CT Scan - A CT (computerized tomography) scan is a non-invasive, painless procedure that usually combines multiple rotating X-Rays along with high end computerized processing to produce more detailed images of the inner structures of a body.
d) PET CT scan - PET CT is a diagnostic imaging test primarily used for detection of cancer and several other disorders. The PET-CT Scan is a test that that combines two scans together i.e. PET scan & CT scan. Positron emission tomography (PET) scan is a nuclear medicine imaging technique which uses small amounts of radioactive material to diagnose or assess a disease, especially cancer.
e) Brain biopsy - A biopsy can be performed as part surgical procedure in which a small part of the tumor is removed with the help of a needle for testing and to determine if the tumor is malignant.
Note: These tests are just for suggestions. Always consult your doctor prior to any test.