The brain and spinal cord form the central nervous system. The brain is located within the skull cavity and is a soft structure and contains nerve cells and other types of cells. The spinal cord is a tube-like structure that is present with the spine and is in continuation with the brain at the top. Together they form the CNS or central nervous system.
Tumours that develop within the brain are called as brain tumours and those that develop within the spinal cord are called as spinal cord tumours.
The tumours can be benign or malignant and the common ones are given below.
Primary brain tumours in children make up the second most common tumours in children after blood related tumours. Brain tumours that can occur in children include low and high grade gliomas, medulloblastoma, Ependymoma, Craniopharyngioma, germ cell tumours and nerve sheath tumours. The commoner ones are given below.
The symptoms associated with these tumours can include symptoms such as headaches, changes in eyesight, fits, drowsiness, confusion, reduced mobility and weakness. Diagnosis is made with the help of scans such as MRI or CT scan of the brain or spinal cord. A biopsy or surgery is done to confirm the diagnosis.
Gliomas are tumours of the brain and spinal cord that develop from the glial cells. They make up 30%-40% of all childhood brain tumours. They develop form astrocytes in the brain and are called as astrocytomas, can develop from oligodendroglial cells and are called as oligodendrogliomas. Low grade gliomas are slow growing tumours.
Treatment options for these tumours include surgery, radiotherapy and chemotherapy. Surgery is usually the first treatment if it is felt that the tumour can be removed without causing excessive side effects. Surgery may be able to remove the tumours completely. In those patients where surgery is not possible or where surgery is incomplete or where the cancer comes back after surgery, radiotherapy is a good option of treatment to help control the disease. The radiotherapy is once a day, 5 days a week for up to 6 weeks. Chemotherapy can be used if there is increase in disease after radiotherapy and the drugs commonly used include Carboplatin and Vincristine.
Gliomas are divided into different grades. Grades 1 and 2 are called as low grade and grades 3 and 4 are called as high grade. High grade tumours tend to be more aggressive, in that they tend to grow faster. Symptoms for high grade gliomas are similar to those of low grade ones except that they may be of shorter duration. A biopsy is done to establish a diagnosis. Surgery is considered if the tumour is in a location where surgery can remove the tumour. Otherwise radiotherapy over 6 weeks once a day, 5 days a week is an option. Chemotherapy such as Carboplatin and Temozolomide are used.
Childhood ependymoma mainly occurs in young children under the age of 5 and make up about 10% of all childhood brain tumours. They arise from the ependymal cells present in the brain.
Ependymomas are best treated with surgery and followed by radiotherapy. Surgery if feasible, offers the best chance of a cure. Radiotherapy is given to the area of the brain where the tumour was present and lasts for up to 6 weeks in duration. Radiotherapy is generally not given to children under the age of 3 as it can affect the development of the brain significantly in these children. Chemotherapy is used when radiotherapy cannot be given or when the cancer comes back after surgery and radiotherapy. Cisplatin based chemotherapy is used in this setting.
Medulloblastoma is a cancer that starts in the part of the brain called the cerebellum. It is the commonest brain tumour in children. It usually occurs at the age of around 5-6 years.
Children with medulloblastoma have the following symptoms. Headaches are common in patients with medulloblastomas. These could be at night or early in the morning. They can be associated with vomiting, nausea and altered behaviour. These tumours can cause in a change in the mobility of the patients. They may be unsteady on their feet. This can be sudden in onset or increase gradually. Patients with medulloblastoma may have a blurred eyesight or may feel dizzy or may have double vision. Patients may gradually become drowsy and may have reduced consciousness due to increased pressure in the brain.
Investigations in Medulloblastoma
When a medulloblastoma is suspected, the following tests are done. An MRI scan of the brain is the first test that is done. MRI is better than a CT scan to see the tumour in the brain. A lumbar puncture is a procedure where a needle is placed into the canal in the spine to get a sample of the fluid (CSF)in the spine. This fluid is examined for the presence of medulloblastoma cells as this tumour can spread through the fluid from the brain to other parts of the spine. A definite diagnosis of medulloblastoma is made once surgery is done and the tumour is removed and looked under the microscope. A separate biopsy is not done as surgery is normally needed anyway and the MRI is good in suggesting a diagnosis.
Staging of Medulloblastoma
Medulloblastoma is staged according to the modified Chang criteria which is given below.
Extent of Tumour
|T1||Tumour less than 3 cm|
|T2||Tumour more than 3 cm|
|T3||Tumour more than 3cm and extension into structures such as aqueduct of the sylvius and/or foramen of Luschka or into brain stem|
|T4||Tumour more than 3cm and extension past the aqueduct of sylvius or
Degree of Metastases
|M0||No evidence of gross metastases|
|M1||Microscopic cells found in fluid in the spine (CSF)|
|M2||Disease seen in the subarachnoid space in the brain or 3rd or lateral Ventricles|
|M3||Disease seen in the subarachnoid space of the spine|
|M4||Presence of metastases outside of the brain or spine.|
Treatment of Medulloblastoma
Surgery, Radiotherapy and Chemotherapy are all used as treatments for Medulloblastoma. The treatment options are different depending the age of the child. For children aged above 3 years and who do not have very advanced disease, the first option of treatment is surgical removal of the cancer in the brain. Following this they have radiotherapy along with chemotherapy which includes drugs such as Vincristine, CCNU and Cisplatin. This radiotherapy is given to the whole brain and the whole spine. This is called as craniospinal irradiation. Initial part of the radiotherapy is to the brain and spine and this is followed up by more radiotherapy to the brain. Chemoradiotherapy lasts for about 6 weeks. Following that, chemotherapy only is used.
For children less than 3 years of age, radiotherapy is not considered in view of the risk of damage to the growing brain at that age. These children are treated with surgery followed by chemotherapy. This chemotherapy is a combination of drugs. In children with advanced disease that is metastatic or not curable, craniospinal radiotherapy followed by chemotherapy is an option of treatment.
Side effects of treatment
As children having above mentioned treatments are young, there is a possibility of side effects from the treatments. These can include reduced development in the brain, hearing loss, decreased growth of the child due to effect of radiotherapy on the spine, reduced function of thyroid gland and other endocrine glands. Children should be on regular check-ups by the doctor to monitor such side effects after treatment.
These are tumours in the brain that start near the pituitary gland. Symptoms produced by this tumour are mainly due to local pressure effects on surrounding structures and include changes in eyesight such as blurred or double vision, headaches, drowsiness etc. Treatment is in the form of surgery as it offers the best chance of cure. If there is remaining disease after surgery or if there is recurrence after surgery, radiotherapy is given to control the disease. This treatment is for up to 6 weeks. Like other childhood brain tumours, radiotherapy is avoided in very young children. Following treatment, the patient should be under close supervision to monitor the function of the pituitary gland.
These are rare tumours seen in children in the brain. Germ cell tumours are those tumours that develop from primitive germ cells that are present in different parts of the body. Tumours within the cranium (skull) occur more commonly in children in the second decade of life. They can be broadly divided into germinomas and non germinomatous germ cell tumours.
Symptoms associated with these tumours include increase in the pressure in the brain leading to headaches, eye symptoms, vomiting, sleepiness. Other symptoms include reduced function of the pituitary gland as these tumours tend to occur close to it.
Diagnosis of these tumours is made by CT or MRI scan, blood tests for beta-HCG, AFP and others and a biopsy of the tumour. CSF analysis is also commonly done and can aid in the diagnosis.
Treatment of intracranial germ cell tumours is dependent on the subtype of germ cell tumour. For patients with a germinoma confined to one area, radiotherapy to the brain is done for 4-5 weeks in total. Radiotherapy to the brain and spine is used in patients where there is more spread of the tumour to these areas.
Treatment of non germinomatous germ cell tumours includes chemotherapy followed by radiotherapy. Chemotherapy is usually a combination of drugs including Cisplatin or Carboplatin drugs. This is given for 3-4 months and followed up with radiotherapy to the brain and spine which can last up to 6 weeks.