The brain tumors are one type of disease characterized by abnormal tissue formation in both the brain and the spinal cord (National Institute of Cancer, 2015). It is an abnormal accumulation of cells that form a mass (National Institute of Neurological Disorders and Stroke, 2016).
Despite the fact that the body of knowledge about this type of neoplasm has progressed considerably in the last decades and that therefore the survival of patients has increased, the prognosis has not changed significantly. Therefore, in its treatment, traditional approaches are still used: surgery, radiotherapy, chemotherapy and introduction of new drugs (Lafuente-Sánchez, 2002).
Cells are the basic structural and functional units for humans. When our body works in a coordinated and normalized way, the normal development path is the formation of new cells to replace old or damaged ones. However, cells can also start to grow abnormally, forming a tumor (Johns Hopkins Medicine, 2016).
This uncontrolled development of cells is due to a mutation or injury of the genes responsible for regulating cell growth and death (National Institute of Neurological Disorders and Stroke, 2016).
When genetic regulatory mechanisms do not work optimally, cells can begin to grow and divide uncontrollably and therefore form tumors in any area of the body (National Institute of Neurological Disorders and Stroke, 2016).
These masses or tumors will cause damage at the neurological level, both due to the pressure they can exert on other brain and spinal structures and due to its spread through different areas (Johns Hopkins Medicine, 2016).
Are all brain and spinal tumors going to cause neurological damage?
In general, all tumors regardless of where they are located can be classified as benign or malignant (Johns Hopkins Medicine, 2016):
It is a non-cancerous cell mass that grows slowly and locally, it does not expand to other areas. The cells that form this tumor are similar to non-pathological ones and are usually removed surgically without reappearing.
It can damage and compress brain areas; when located in vital areas they can be life threatening Johns Hopkins Medicine, 2016).
It is a mass made up of cancer cells, they tend to grow faster and more globally and spread to other areas. In addition to the use of surgery, chemotherapy and radiotherapy are frequent for its treatment. In general, malignant tumors seriously threaten the life of the person who suffers from them Johns Hopkins Medicine, 2016).
Regardless of whether it is a benign or malignant tumor, all the masses that grow in or invade brain tissue are potentially capable of damaging the different neurological functions.
Although some of the brain tumors can spread to other areas of the body, most of them tend to spread between neural tissue, both malignant and benign tumors (Johns Hopkins Medicine, 2016).
Consequences at the brain and spinal level
Depending on the type, tumors can cause different events at the brain and spinal level (National Institute of Neurological Disorders and Stroke, 2016):
- Damage or destroy healthy cells.
- Damage or disrupt the function of healthy cells.
- It can displace or press the surrounding tissue.
- They can block blood flow causing inflammation, obstruction, hypoxia, among others.
- It can block the flow of neural information by damaging pathways to stimulate entry or exit.
Although the most common is the appearance of extensive symptoms, there have also been documented cases in which the presence of a brain or spinal cord tumor is asymptomatic.
Types of brain and spinal tumors
Clinical and experimental reports have identified more than 120 types of brain and spinal tumors. All these types can be classified by the place of origin and expression, by the type of cells that originate them and / or by the specific location in which they are found (National Institute of Neurological Disorders and Stroke, 2016).
-Depending on the origin and expansion
Normally in the scientific literature, depending on the origin and expansion of this type of tumor, we speak of primary or metastatic tumors:
Cells begin to grow locally in the central nervous system . They can be benign or malignant and occur preferably in adults (National Institute of Neurological Disorders and Stroke, 2016). The most prevalent are meningiomas and gliomas (Johns Hopkins Medicine, 2016).
The primary tumor of a cancerous or malignant type is generated in another part of the body and expands to regions of the central nervous system (National Institute of Neurological Disorders and Stroke, 2016).
Approximately 50% of metastatic brain and medullary tumors are the product of lung cancer, although they can also lead to melanomas, breast cancer, kidney cancer and nasopharyngeal cancer (National Institute of Cancer, 2015).
-Depending on the type of originating cell
Depending on the original cell type or the part of the brain or spinal cord where it is located, some of the most prevalent types in both children and adults are (National Institute of Neurological Disorders, 2016):
Tumors derive from glial cells (cells that support different neuronal functions). They usually occur in the cerebral hemispheres and in other areas such as the optic nerve, the brain stem, or the cerebellum . We can make a classification of gliomas based on what type of glial cell is affected:
- Atrocytomas : develop from astrocytes. They are the cause of approximately 50% of central nervous system tumors. The most common forms are: anaplastic astrocytoma, polycytic astrocytopa, glioblastoma multiforme.
- Ependymomas : develop from cells that line the aqueducts and cavities of the brain and the spinal canal, where cerebrospinal fluid is produced and stored . It is usually of the benign type.
Other tumors that may appear include:
It develops in the spinal column, they are usually congenital and can invade both the spinal canal and the brain.
Choroid plexus papillomas
They essentially affect the production of cerebrospinal fluid by increasing its production or blocking normal flow.
They usually grow in the brain base, in regions close to the pituitary gland, optic nerve and surrounding tissue. They are usually of the congenital type.
Dembryoplasmic neuroepithelial tumors
They usually develop in the upper half of the brain. Although they are generally beningo, they cause a significant number of seizures.
Germ cell tumors
They develop from cells that do not migrate during the development of the central nervous system to differentiate into a specific organ. They usually form inside the brain , near the pineal gland and can spread to other brain and spinal areas. Depending on the type of germ cell that originates it, we can find teratomas, embryonic carcinomas and germinomas.
They develop in the membranes that protect the brain and spinal cord, the meninges. They are generally benign and do not tend to invade adjacent tissues.
Primitive neuroectodermal tumors
They usually develop from primitive or immature cells that are present during the development of the nervous system. It can spread throughout the brain and spinal cord in an irregular way. There are two very common types:
- Medulloblastomas : They occur in more than 25% of childhood brain tumors. They are normally generated in the brain and can spread throughout the entire spinal cord.
- Neuroblastomas : they usually develop above the adrenal glands, but can be located in other areas of the brain and spinal cord.
They develop in the blood vessels that supply the brain and spinal cord.
As we have seen there are a wide variety of tumors, therefore the symptoms will vary depending on the location of the tumor. In addition, the size and rate of growth will also determine the clinical course of the symptoms (Johns Hopkins Medicine, 2016).
Some of the most common symptoms that can appear are (Johns Hopkins Medicine, 2016):
- Headaches or headaches
- Seizure episodes.
- Difficulty concentrating or speaking.
- Changes in personality
- Behavioral changes
- Weakness or paralysis of a specific part of the body or an entire side.
- Hearing loss.
- Loss of vision
- Confusion and disorientation.
- Forgetfulness and memory loss.
These symptoms are often classified depending on whether the origin is in a brain or spinal tumor (National Institute of Cancer, 2015):
- Symptoms of brain tumors: morning headache relieved by vomiting; convulsive crisis; vision, hearing or speech problems or difficulties; loss of appetite; recurring nausea and vomiting; changes in personality, mood, behavior, or ability to concentrate; loss of balance or difficulty walking; weakness and exaggerated sleepiness (National Institute of Cancer, 2015).
- Symptoms of spinal tumors : pain in the back that spreads to the extremities; change in bowel habits or difficulty urinating; weakness and numbness in the legs and arms; difficulty walking (National Institute of Cancer, 2015).
Current clinical research does not yet know the causes of the development of primary brain and spinal tumors. Some of the causes that are being investigated are: viruses, genetic mutations, exposure to chemicals or hazardous materials and disorders of the immune system (National Institute of Neurological Disorders and Stroke, 2016).
On the other hand, it is known that the consumption of alcohol and tobacco or different unhealthy dietary habits are associated with some types of cancer, but none of them have been related to the presence of primary tumors in the central nervous system (National Institute of Neurological Disorders and Stroke, 2016).
There is a small number of patients in whom some specific genetic causes have been identified: neurofibromatosis and tuberous sclerosis (National Institute of Neurological Disorders and Stroke, 2016).
Who gets brain or spinal tumors?
Statistical estimates estimate that there may be more than 359,000 people in the United States living with a CNS tumor diagnosis. In addition, more than 195,000 new cases are diagnosed each year (National Institute of Neurological Disorders and Stroke, 2016)
In general, brain tumors are more common than spinal ones. They can occur at any age; however, they are more common in middle-aged and young adults (National Institute of Neurological Disorders and Stroke, 2016)
Despite this, approximately more than 3,200 tumors of the central nervous system are diagnosed in children each year (National Institute of Neurological Disorders and Stroke, 2016).
Risk factors for tumors in the central nervous system
Some studies have shown that there are some conditions that can increase the risk of developing these types of tumors (Cancer Support Community, 2016):
- Exposure to vinyl chloride.
- Epsein-Barr virus infection.
- Organ transplantation.
- Primary CNS lymphoma.
In addition, some genetic factors have also been identified (Cancer Support Community, 2016):
- Neurofibromatosis type 1 or 2.
- Tuberous sclerosis.
- Li-Fraumeni syndrome.
- Turcot syndrome type 1 and type 2.
- Klinefelter syndrome.
- Basal cell carcinoma syndrome.
Treatments for central nervous system tumors will depend on several factors: size, location, symptoms, general health, and treatment preferences. Some of the most used treatments are:
In some patients the combined use of these therapies is possible, while in others the exclusive use of one of them is beneficial.
- ACS. (2016). Brain and Spinal Cord tumors in Adults . Retrieved from American Cancer Society: cancer.org
- CSC. (2016). Brain and Spinal Cord Tumors . Obtained from Cancer Support Community:
- NHI. (2016). Adult Central Nervous System Tumors Treatment . Retrieved from National Cancer Institute: cancer.gov
- The Jhons Hopkins University. (2016). About Brain Tumors . Retrieved from Jhons Hopkins Medicine: hopkinsmedicine.org