Brain tumours are the most common solid tumours out of all types that occur in children – 25% of all childhood cancer. Children of any age may be affected. Boys and girls are almost equally affected (Medulloblastomas & Germ Cell Tumours are slightly more predominant in boys).
Among the 12 major types of childhood cancers, Leukaemia (blood cell cancers) Lymphomas and cancers of the brain and central nervous system account for more than half of the new cases.
Brain tumours can be either primary or secondary. Primary brain tumours are tumours which develop in the brain. Secondary brain tumours (more commonly called cerebral metastases) occur when cancer cells from other parts of the body spread to the brain. Malignant primary brain tumours are most likely to cause problems by causing pressure and damage to the areas around them and possibly by spreading to the normal brain tissue close by.
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.
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).
Diagnosis & Investigations:
• 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.