Brain tumors are the most common solid tumors affecting children and adolescents with close to 5,000 children diagnosed each year in the US alone. Because of their location, some pediatric brain tumors and their required treatments can cause significant long-term impairment to intellectual and neurological function. Some forms of brain tumor can be life-threatening.
Pediatric brain tumors are masses of abnormal cells that result from uncontrolled growth of cells that occur in children. A tumor develops if the DNA mutations in any of the brain cells leads to an abnormal growth of cells or uncontrolled cell division. Some of these tumors are benign and stay well-contained or localized. But some become malignant and these are the ones that break through and invade nearby tissues. Malignant tumor cells get into cerebrospinal fluid (CSF) and travel from the primary site to establish a secondary site of tumor growth elsewhere in the brain or spine. This is called metastatic brain tumor.
Causes of brain tumors:
There are very few known and established causes of brain tumors is children. They are:
Research reports that gene changes that cause some rare inherited syndromes (like neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome and von Hippel-Lindau syndrome) also increase the risk of brain tumors.
Severe radiation exposures to certain substances can also cause brain tumors. Other than radiation, no known lifestyle-related or environmental factors are clearly linked to brain tumors. Most gene changes are probably just random events that sometimes happen inside a cell, without having an outside cause.
Signs and symptoms of pediatric brain tumors
Signs and symptoms of a brain tumor in children depend on the brain tumor type, size, location and rate of growth. These symptoms are caused due to the compression and destruction of healthy brain tissues.
- Personality and mental activity changes
- Macroencephaly (enlarged head in infants) whose skull bones are not completely fused
- Coma and death (if left untreated)
Other possible signs and symptoms depend on the tumor location. Increased intracranial pressure from tumor cells can cause symptoms like:
- A fuller soft spot on the skull in babies aged less than 1 year
- Abnormal eye movement
- Slurred speech
- Trouble swallowing
- Loss of appetite; or in babies, difficulty feeding
- Difficulty with balance
- Trouble walking
- Weakness or loss of sensation in an arm or a leg
- Weakness or drooping on one side on the face
- Confusion, irritability
- Memory problems
- Hearing problems
Generally the diagnosis of central nervous system tumors includes medical imaging like CT scans but more commonly MRIs. Definitive diagnosis, regardless, needs to be made based on molecular characteristics of a tissue biopsy If the scan shows a brain tumor, the next step is a neurosurgical consultation. The pediatric neurosurgeon discuss with the whole family to develop the best treatment plan for the child. Read more on treatment of brain tumor.
Other specialists may join the child’s treatment team, such as a neurosurgeon, a radiation oncologist, an ophthalmologist (if the child’s tumor affects the vision pathways), an epileptologist (for seizures), and advanced practitioners and technologists.
Types of Brain Tumors in Children
Brain tumors can be grouped in four categories:
- Primary tumors are those that start in the brain.
- Metastatic tumors start in other parts of the body and spreading to the brain.
- Benign tumors are those which are slow-growing and non-cancerous. Benign tumors can still be difficult to treat if they are growing in or around certain structures of the brain.
- Malignant tumors are cancerous. Unlike benign tumors that tend to stay contained, malignant tumors can be very aggressive. They grow rapidly and can spread to areas near the original tumor and to other areas in the brain.
Treatment depends on tumor type, grade and symptoms. They can include surgery, chemotherapy and radiation- frequently in a combination. But specific courses of treatment are guided by the molecular characteristics of the tumor based on the biopsy. The chance of recurrence gets higher in high grade tumors and in tumors that have not been fully removed or destroyed. Overall the treatment for a child with brain tumors typically lasts over up to 3-6 months depending on the treatments required for the tumor and rehabilitation.
Surgery: Most brain tumors in children require treatment by surgical removal. The surgeon may recommend surgery to remove as much of the tumor as safely possible as a first step and to relieve intracranial pressure caused by the tumor. For low-grade or slow-growing tumors, surgery may be the only intervention necessary.
Radiation Therapy: This therapy focuses beams of high-energy radiation on the tumor tissue and a small amount of surrounding tissue. Some tumors, such as medulloblastoma, require additional radiation to the entire brain and spinal cord. Radiation is used very cautiously in infants and toddlers due to their growing brains. Proton-beam therapy is another growing technology in med-tech that has shown great promise. Read more about it on Dr Srinivas Chilikuri’s article Survivorship and beyond in childhood cancers - Impact of proton therapy.
Chemotherapy: Chemotherapy for pediatric brain tumors is used for many types of brain tumors including aggressive, high-grade tumors. This can be administered as pills (orally), intravenously (IV, by vein), injected directly into the cerebrospinal fluid, or injected directly into the cavity left after surgical removal of a brain tumor.
Follow-up Care after Surgery
The recovery process is different for each child. Children who received prompt diagnosis and treatment do well after surgery. Some pediatric patients may experience some temporary neurological deficits, such as muscle weakness. In most cases, this goes away shortly after surgery, unless there was substantial permanent damage before the child was diagnosed. Physical, occupational and speech therapy can help improve strength, function and speed of recovery. Regular post-operative follow-up visits with the child’s neurosurgeon are also important to monitor neurological function and side effects from treatment, and to guard against recurrence of the tumor.
Palliative Care and Follow-up for Brain Tumor
Palliative care helps make sure that children diagnosed with a brain tumor have the best quality of life. It is supportive care which prevents, treats and controls the symptoms and side-effects of a disease and its treatment. It is a holistic approach to treating different aspects of cancer: the emotional, social, practical and spiritual aspects.