Medulloblastoma is a brain cancer that usually occurs in children and young adults. Like all cancers, it is caused by the unbridled growth of abnormal cells that continue dividing without control. Over a period of time, these cells form a tumor or lump in the brain that keeps getting bigger. Medulloblastoma can spread to nearby parts of the brain and spinal cord, but not usually to other parts of the body. Brain tumors like medulloblastoma press on normal parts of the brain causing problems in brain function. This pressure on the brain causes symptoms such as headache, loss of balance, nausea, vomiting, and sleepiness, which are often worst in the morning.
In addition to pressure directly on the brain, medulloblastoma grows in a space that gets blocked off as the tumor gets larger. Medulloblastoma is most common in young children. The typical age at the time of diagnosis is around 7-8 years old, but it can occur in younger children as well as in adults. The tumor appears most often in the part of the brain where the cerebellum, fourth ventricle and brain stem meet. Medulloblastoma starts in this area but easily invades nearby tissue or spreads (metastasizes) to other parts of the brain and spinal cord. As many as 30% of patients have disease spread at the time the tumor is first diagnosed. But less than 5% of patients have tumor spread anywhere else in the body. If it spreads outside the brain and spinal cord, it usually goes to the bones.
To make a timely and accurate diagnosis of Medulloblastoma, many questions about a patient’s general health are asked. After the patient’s health history, a thorough physical exam is done. The most important part is a test of all the brain and spinal cord functions called a neurological exam. This helps to match up the history with the physical findings. When the history and physical exam are complete, some other tests may be done. Some blood tests are done just to check the patient’s general state of health. Other tests are specially for diagnosing a brain tumor. The most useful are a CT scan and MRI of the brain. These imaging tests can show the location and size of the tumor. It also shows what effect the tumor has on other parts of the brain. The location of a tumor in the fourth ventricle and cerebellum and its particular appearance of the tumor on the MRI image makes a diagnosis of medulloblastoma likely. The diagnosis of medulloblastoma can be made with some certainty from the history, physical exam, and the CT and/or MRI. But confirming the diagnosis only happens after the tumor is removed and a pathologist looks at the tumor tissue under a microscope.
The treatment used for medulloblastoma will depend on where the tumour is, if it has spread and the age of the child. Typically the treatment will include the following components:
Surgery: The patient might have to undergo an operation to confirm the diagnosis, relieve pressure and try to remove as much of the tumour as possible.
Radiotherapy: Radiotherapy is often used after surgery to destroy any remaining malignant cells. As medulloblastoma / PNET may spread through the cerebrospinal fluid to the spinal cord, radiotherapy is given to the brain and spinal cord.
Chemotherapy: Chemotherapy is given together with surgery and or radiotherapy to treat the tumour. Treatment with anti-cancer drugs is used to destroy the cancer cells. It is usually given by injections and drips into a vein (intravenous infusion). The type of chemotherapy will vary according to whether the tumour has spread, if radiotherapy is to be used and the age of the child. Some children may need high-dose chemotherapy with a stem cell transplant.
Our doctors have access to and proven expertise of the entire range of cutting edge technologies and procedures for treating brain cancers. A few examples:
- Stereotactic radiosurgery
- Computer-aided surgery
- Targeted drug therapy
- Awake brain surgery
In addition to these, the following procedures may be ordered for diagnosis:
Pet scan( Positron Emission Tomography): These scans require an injection of glucose (a sugar molecule) that has been made mildly radioactive. The brain uses the glucose for energy. Some parts of the brain use more glucose than others. The PET scanner picks up the amounts of radioactivity coming from different parts of the brain as the glucose is used up. When a tumor is present, it shows on the PET scan because the tumor cells use an abnormal amount of the radioactive glucose.
MRI: A spine MRI along with a brain MRI. Contrast dye makes the MRI more capable of showing areas of abnormal cells.
Spinal tap: Another test called a spinal tap is done 10 – 14 days after surgery. A spinal tap removes a small amount of CSF (cerebrospinal fluid) so it can be tested for tumor cells. It is done by putting a long, thin needle in the space between the spinal bones and the spinal cord. This is the space the CSF flows through.