What are Pediatric Brain Tumors?
Pediatric brain tumors are defined as growths of abnormal brain cells in a child. A brain cell becomes abnormal when it undergoes genetic changes. The change in a specific gene of brain cells can cause the cell to form a tumor. These tumors can be either benign (non-cancerous) or malignant (cancerous).
A benign tumor does not contain cancer cells and usually, once removed, does not recur. Most benign brain tumors have clear borders, meaning they do not invade surrounding tissue. These tumors can, however, cause symptoms similar to cancerous tumors because of their size and location in the brain.
Malignant brain tumors contain cancer cells and are usually fast-growing and invade surrounding tissue. They very rarely spread to other areas of the body, but may recur after treatment. Sometimes, brain tumors that are not cancerous are called malignant because of their size and location, and the damage they can cause to vital functions of the brain.
Anatomy
The central nervous system (CNS) consists of the brain and spinal cord. The brain is an important organ that controls thought, memory, emotion, touch, motor skills, vision, respiration, temperature, hunger, and every process that regulates our body. The brain is contained within the skull, which protects it. There are 3 layers of membrane called the meninges between the brain and the skull. These completely cover the brain and spinal cord and help to protect it. Between 2 of these layers is a space that contains a fluid called cerebrospinal fluid (CSF), which circulates around the brain and spinal cord. It performs vital functions, including providing nourishment, waste removal, and protection to the brain. The main parts of the brain are:
- Cerebrum: This is at the top of the head and is the largest part of the brain. It is composed of the right and left hemispheres. Functions of the cerebrum include initiation of movement, temperature sensation, touch, vision, hearing, judgment, reasoning, problem-solving, emotions, and learning.
- Cerebellum: This is the back part of the brain, and it controls functions such as movement, balance, and coordination.
- Brain stem: This connects the brain to the spinal cord and is in the lower part of the brain just above the back of the neck. It controls functions such as breathing, body temperature, heart rate and blood pressure, eye movements, and swallowing.
Types of Pediatric Brain Tumors
There are different types of pediatric brain tumors, and they can be classified based on their location, the type of cells involved, and their behavior (benign or malignant). Common types include medulloblastomas, gliomas, ependymomas, and craniopharyngiomas.
Causes of Pediatric Brain Tumors
The exact causes of pediatric brain tumors are often not well understood, and in many cases, the development of these tumors is thought to result from a combination of genetic and environmental factors. While the specific cause of an individual's brain tumor may not be definitively identified, researchers have identified some factors that may be associated with an increased risk of developing pediatric brain tumors, such as:
- Genetic factors
- Family history
- Radiation exposure
- Viral infections
- Environmental factors
Symptoms of Pediatric Brain Tumors
The skull does not have excess space for anything other than the brain. Consequently, as brain tumors develop and expand, they cause extra pressure in this closed area. This is known as intracranial pressure. Increased intracranial pressure is caused by extra tissue in the brain as well as blockage of the cerebrospinal fluid flow pathways. The signs and symptoms of pediatric brain tumors can vary depending on the type of tumor, its location, and its size. Some common signs and symptoms include:
- Headaches
- Nausea and vomiting
- Seizures
- Irritability
- Personality and mental activity changes
- Lethargy and drowsiness
- Macroencephaly (enlarged head)
- Balance and coordination problems
- Balance and coordination problems
- Speech difficulties
- Visual changes
- Cognitive changes
- Hormonal changes
- Coma and death, if left untreated
Diagnosis of Pediatric Brain Tumors
The diagnosis of pediatric brain tumors involves a combination of medical history assessment, physical examination, and various diagnostic tests. The process may include:
- Medical History: The healthcare provider will gather information about the child's symptoms, medical history, and any family history of cancer or genetic conditions.
- Physical Examination: A thorough neurological examination is conducted to assess the child's coordination, reflexes, vision, and other neurological functions.
- Imaging Tests:
- MRI (Magnetic Resonance Imaging): This imaging technique provides detailed pictures of the brain and helps identify the location, size, and characteristics of the tumor.
- CT (Computed Tomography) Scan: CT scans may be used to provide additional information about the tumor's characteristics, particularly if an MRI is not feasible.
- Positron Emission Tomography (PET) Scan: A PET scan may show areas of cancer that may not be seen on a CT scan or an MRI scan.
- Biopsy: In some instances, a biopsy may be performed to obtain a sample of the tumor tissue for laboratory analysis. This can help determine the type of tumor and its grade (benign or malignant). Biopsies can be done through surgery or, in certain cases, using less invasive procedures such as stereotactic biopsy.
- Lumbar Puncture (Spinal Tap): A lumbar puncture may be performed to analyze the cerebrospinal fluid for the presence of cancer cells or other abnormalities. This is especially relevant for tumors located in or near the ventricles.
- Blood Tests: Blood tests may be conducted to assess overall health, organ function, and to detect certain markers that may be associated with specific types of brain tumors.
Treatment for Pediatric Brain Tumors
The treatment for pediatric brain tumors varies depending on factors such as the type of tumor, its location, size, and the overall health of the child. A multidisciplinary approach involving a team of healthcare professionals, including pediatric neurosurgeons, oncologists, radiation oncologists, and other specialists, is often employed. The primary treatment modalities for pediatric brain tumors include:
- Surgery: Surgical removal of the tumor is a common treatment approach when feasible. The goal is to remove as much of the tumor as possible without causing damage to critical brain structures. In some cases, complete removal may not be possible, and a partial resection may be performed.
- Steroids (to treat and prevent swelling in the brain)
- Anti-seizure medication (to treat and prevent seizures associated with intracranial pressure)
- Ventriculoperitoneal shunt (Also called a VP shunt). A VP shunt may be placed in the head to drain excess fluid from inside the brain to the abdomen. A VP shunt helps control the pressure inside the brain.
- Radiation Therapy:
- External Beam Radiation: High-energy rays are directed at the tumor from outside the body. Radiation therapy may be used after surgery to target any remaining cancer cells or as the primary treatment for tumors that are difficult to surgically remove.
- Proton Therapy: This specialized form of radiation therapy delivers targeted radiation to the tumor while minimizing exposure to surrounding healthy tissues.
- Chemotherapy: Chemotherapy involves the use of drugs to kill or inhibit the growth of cancer cells. It may be administered orally, intravenously, or directly into the cerebrospinal fluid, depending on the type of tumor and the treatment plan. Chemotherapy is often used in combination with surgery and/or radiation therapy.
- Targeted Therapies: Some pediatric brain tumors may have specific molecular targets that can be targeted with specific drugs. Targeted therapies are designed to interfere with specific molecules involved in cancer growth and progression.
- Rehabilitation Services: Rehabilitation services, including physical therapy, occupational therapy, and speech therapy, may be recommended to help manage the impact of the tumor and its treatment on the child's physical and cognitive function.
