Most common types of brain tumours that affect children are gliomas (60%), medulloblastomas (20%) & ependymomas (10%). Other types are glioma of optic nerve, chiasma & hypothalamus, primitive neuro-ectodermal tumour (PNET), choroid plexus tumour, germ cell tumour, craniopharyngioma, pineal cell tumour, neuroblastoma, meningioma. Less than 5% of central nervous system tumours are spinal origin.
The incidence of childhood brain tumours rose from 1975 through 2009, from 2.3 to 3.2 cases per 100,000. From 1983 through l986 there was the greatest increase in incidence of Brain tumours all over the world due to
- MRI brain scans (new facility) allowed doctors to visualise those brain tumours that could not be easily visualised previously with older equipment
- Revised classification of brain tumours resulted in tumours previously designated as “benign” (harmless) being reclassified as “malignant” (cancerous).
- Neuro-surgical progress - improved techniques for biopsying brain tumours.
Although the cause of brain tumours is unknown, research is ongoing to find the cause.
There are several possible risk factors for childhood cancers, e.g, early-life exposures to infectious agents; parental, fetal, or childhood exposures to environmental toxins such as pesticides, solvents, or other household chemicals; parental occupational exposures to radiation or chemicals; parental medical conditions during pregnancy or before conception; maternal diet during pregnancy; early postnatal feeding patterns and diet; and maternal reproductive history etc. Researchers are also studying the risks associated with maternal exposures to oral contraceptives, fertility drugs, and other medications; familial and genetic susceptibility; and risk associated with exposure to the human immunodeficiency virus (HIV).
Brain tumours may cause a wide variety of symptoms depending on the age of the child. These are usually caused by a rise in pressure within the brain (raised intracranial pressure). The tumour if large enough, may block the flow of the cerebrospinal fluid (CSF) around the brain (this is called hydrocephalus).
- Young babies may present with bulging of the soft spot on their head with protrusion of eyes & their head may increase in size.
- Infants may present with irritability, lethargy, vomiting, failing to gain adequate weight, developmental regression, unusually large head size.
- Young children & adolescents may present with headache & vomiting (both specifically in the morning), personality change, more specific signs e.g, unsteady on feet, blurring of vision, squint of either eyes, weakness of limbs etc.
- Symptoms of drowsiness, irritability, fits (seizures) or moments of unconsciousness might warrant urgent medical attention due to significant disease progression.
Diagnosis & Investigations:
- Detailed history & careful examination are essential to identify the signs of brain tumour. Detailed examination of the eyes can show intracranial pressure.
- MRI scan of brain & spine is the most suitable tests.
- Brain angiogram (shows the structure of the blood vessels in the brain) is sometimes used to help plan surgery.
- CSF cytology to identify type of brain tumour
- Biopsy of the tumour after its operative removal to find out exactly which type of tumour it is.
- Blood tests may diagnose a particular type of tumour called a germ-cell brain tumour.
- A chest x-ray and blood tests may be needed to check your child’s general health.
- Surgical Resection: Complete surgical resection of the tumour is the ideal management, but it only depends on the location of the tumour. Following the gross total resection of the tumour, radiotherapy to the tumour bed and a margin of surrounding brain as well as adjuvant chemotherapy may extend the survival depending on the type of tumour. (High-grade gliomas, glioblastoma multiforme, medulloblastoma, craniopharyngioma, germ cell tumours need combinations of radiotherapy and chemotherapy).
- Radiotherapy: If a tumour cannot be completely removed, or if there is a chance that some cancer cells have been left behind, radiotherapy may be given after the surgery (high-energy rays that destroy the cancer cells). It may be the main treatment if surgery is not possible. Radiotherapy is usually deferred in very young children if possible.
- Chemotherapy: It is used routinely to treat medulloblastoma and is increasingly being used to treat other types of brain tumours. Chemotherapy may also be used in situations where the tumour cannot be removed completely with surgery. It can be given in the form of tablets, or by injection into a vein (intravenously).
- Shunt: Management of the hydrocephalus also equally important which might need surgical insertion of either an internal V.P shunt or an external ventricular drain (EVD) in the brain or by treatment with medicine.
- Anticonvulsant: These medicines might be needed to control fits / seizures if present.
- Steroids: Steroid reduces swelling surrounding the brain tumour. Hormone replacement therapy might be needed in a few cases of brain tumour.
Complications of cranial irradiation:
Initially child may complain of drowsiness, nausea, headache & lethargy. Long term complications could present as alopecia (loss of scalp hair), dental problem, hearing loss, stunted growth, behaviour & psycho-social problem etc.
Posterior Fossa Syndrome (Mutism):
After resection of tumour of posterior fossa, sometimes patients develop mutism, finds difficulty to speak, when language is particularly affected, reduced oral intake, becomes unsteady on feet, becomes incontinent of urine or stool. These happen more commonly in adults.
As there are different types of brain tumours with varying grades of severity, their prognosis are also variable.
Low-grade gliomas & cerebellar astrocytomas following good surgical resection, are associated with 75% and 90 % 5 yr survival respectively. For medulloblastoma with standard risk, 5 yr survival is usually 80%. Ependymoma with standard risk, 5 yrs survival is 50-60%. In case of High-grade gliomas, even with gross resection & adjuvant therapy, 5 yrs survival is only 20-40%.
Life-threatening cases at IN-K & their prompt management:
- A young boy of 9 yrs age presented on 13th of Aug 2010 with history of intermittent vomiting with episodes of eye rolling upwards & headache for 2 months. He became very unsteady on his feet & kept his head tilted in front with pain in back of his neck & upper spine. His diagnosis was confirmed after he was seen in the clinic & had urgent brain MRI performed within 30 mint of presenting in IN-K. Large brain tumour was diagnosed immediately & life-saving neuro-surgical treatment was offered to the child.
- Another boy of age nearly 9 yrs, presented to IN-K on 29th Dec 2010 after having double vision & blurred vision in one eye seeing by tilting his head to Left side, with head for a few days. He was found to have very large high grade glioma brain tumour already compressing & distorting his brain significantly. Immediate surgical intervention was offered to the family.
Please contact Dr R Samanta, Consultant Paediatric Neurologist, at IN-K on tel: 033-2286-9999 for appoitment & further information on the services available for children with Epilepsy at IN-K.