Brain cancer is a disease in which we see cancerous/malignant tumors in the brain. Some brain cancers occur when a type of cell alters its normal characteristics. These are abnormal cells that grow into a mass or tumor. These brain tumors that start in the brain are called primary brain tumors. Tumors that do not invade nearby tissues or spread to other areas are called benign tumors, while those that do are malignant/cancerous tumors. Malignant tumors grow to form a mass of cancerous tissue that interferes with brain functions, such as muscle control, sensitivity, memory, and other normal bodily functions. When cancerous tumors spread from other sites in the body to the brain, they are called metastatic or secondary brain tumors.
It is also important to note that while a benign tumor is less serious than a malignant tumor, it can still cause many problems in the brain by pressing on nearby tissue. Therefore, it is recommended that these benign tumors be monitored and/or treated as recommended by physicians.
Symptoms of brain cancer usually develop over time and their characteristics depend on the location and size of the tumor. Brain cancer symptoms include:
- Behavioural and emotional changes
- Impaired judgment
- Impaired sense of smell
- Memory loss
- Reduced mental capacity
- Inflammation of the optic nerve
- Impaired speech
- Inability to write
- Lack of recognition
- Difficulty in speaking and swallowing
- Headache, especially in the morning
- Loss of hearing
- Muscle weakness on one side of the face
- Uncoordinated gait
- Mental and emotional changes
- Prolonged drowsiness (somnolence)
- Loss of vision
Primary brain tumors can develop in different parts of the brain. Common types of primary brain tumors are gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and primitive neuroectodermal tumors, also called medulloblastoma. Glioma also includes glioblastoma, astrocytoma, oligodendroglioma, and ependymoma.
Metastatic brain cancer is caused by the transfer of cancer cells from the body to the brain. However, the causes of the alteration of normal cells to cancer cells in primary and metastatic brain tumors are not yet fully understood. Research shows that people with certain risk factors are more likely to develop brain cancer.
People with risk factors, such as having a job in an oil refinery, jet fuel handlers, or chemicals like benzene, chemists, embalmers, and workers in the rubber industry, show higher rates of brain cancer than the general population. Some families have multiple members with brain cancer; however, heredity/genetics have not been proven to cause brain tumors. Other risk factors such as smoking, radiation exposure, and viral infections such as HIV have been suggested, but have not been shown to cause brain cancer.
The initial test is a medical interview and a physical examination of the person by the doctor. Findings from this will indicate if there is a problem in the brain or brainstem.
The most widely used test for the diagnosis of brain cancer is a CT scan. This screening procedure is similar to an X-ray sequence and is not unpleasant, but a dye must often be inserted into a vein to obtain clearer images of certain structures inside the brain. Another test that is gaining popularity due to its high sensitivity for detecting structural changes in the brain is magnetic resonance imaging (MRI). This test also looks like a series of X-rays and shows brain structures in better detail than a CT scan. MRI is not as widely available as a CT scan.
People with brain cancer often have other medical problems, too. Therefore, routine laboratory tests can be performed. These include blood tests, electrolytes, and liver function.
If the scans show signs (tumors or brain tissue defects) of brain cancer, other doctors, such as neurosurgeons and neurologists who specialize in treating brain diseases, can be contacted to help decide how to treat the case. Occasionally, a tissue sample (biopsy) may be collected by surgery or by inserting a needle to help evaluate the diagnosis. The healthcare provider may recommend other evaluations to help assess the patient's health status or to diagnose other health problems.
The treatment plan is made by doctors who specialize in brain cancer, and treatments vary widely based on the type of cancer, the location of the tumor, the size of the tumor, the patient's age, and the patient's general health. . An important part of the plan is also determined by the wishes of the patient. Most brain cancer treatment plans are complex and may involve several consulting physicians.
Surgery, chemotherapy, and radiation therapy are the main categories of treatment for most brain cancers.
Surgery aims to kill all tumour cells by cutting the tumour apart from natural brain tissue. This procedure is sometimes referred to as invasive surgery to differentiate it from non-invasive radiosurgery or radiation therapy mentioned below.
Radiation therapy attempts to destroy tumor cells in the brain by using high-energy radiation focused on the tumor to destroy the ability of tumor cells to function and replicate. Radiosurgery is a non-surgical procedure that delivers a single high dose of radiation specifically guided using extremely intense gamma rays or x-rays that are superimposed on the same region or regions of the brain where the tumor or other abnormality is located. This reduces the amount of radiation to healthy brain tissues.
The equipment used to perform radiosurgery varies in its source of radiation; a gamma knife uses focused gamma rays while a linear accelerator uses photons and heavy-charge particle radiosurgery uses a proton beam.
Chemotherapy tries to kill tumor cells by using chemicals (drugs) that are designed to kill specific types of cancer cells. Many chemical agents are used. Specific drug treatments are numerous and each regimen is generally designed for a specific form of brain cancer and individualized for each patient. Chemotherapy can be administered intrathecally, intravenously, and chemically impregnated biodegradable polymers.
Other treatment options may include hyperthermia (heat treatments), immunotherapy (immune cells aimed at killing certain types of cancer cells), or steroids to reduce inflammation and swelling of the brain. These can be added to other treatment plans.