Medulloblastoma Overview

In most cases, the cause of medulloblastoma is not known. In some cases, medulloblastoma is associated with certain inherited diseases, including:

• Li-Fraumeni syndrome
• Nevoid basal cell carcinoma syndrome (Gorlin syndrome)
• Turcot syndrome

It’s important to understand that these and other brain tumors most often occur with no known cause. There’s nothing that you could have done or avoided doing that would have prevented the tumor from developing.

Brain tumors can cause a variety of symptoms in children based on their age and the location of the tumor. Keep in mind that the symptoms of medulloblastoma may resemble other more common conditions or medical problems. Always consult your child's physician for a diagnosis.

While your child may experience symptoms differently, common medulloblastoma symptoms include:

• headache (generally upon awakening in the morning)
• nausea and vomiting
• fatigue
• lethargy
• imbalance and lack of coordination
• problems with motor skills (such as writing)
• neck tilt or double vision
• changes in personality or behavior
• seizures

Rarely, medulloblastoma can spread into the central nervous system or the spinal canal, and your child may experience:

• loss of strength in the lower extremities
• back pain
• bowl and bladder control issues
• difficulty walking

The first step in treating your child is forming an accurate and complete diagnosis.
Your child’s physician may order a number of different tests to determine the type and location of the tumor. In addition to a physical exam, a medical history and neurological exam, diagnostic procedures for medulloblastoma may include:

• Magnetic resonance imaging (MRI): This diagnostic procedure produces detailed images of structures within the brain and spine. An MRI scan of the brain after surgery will determine how much of the tumor was removed surgically.
• Surgical resection: After surgical removal of the tumor a tissue sample will be taken and analyzed to confirm the diagnosis. While an MRI may indicate a possible medulloblastoma, only a tissue sample can confirm the diagnosis.
• Histological diagnosis: The tissue sample obtained from surgery will be reviewed by a neuropathologist, who looks at the tumor under the microscope to confirm whether it has the features of medulloblastoma. We also perform a number of molecular tests to determine the subtype of medulloblastoma. All children undergoing resection of brain tumors at Dana-Farber/Boston Children’s are also invited to participate in our ongoing genetic tumor profiling research studies. These studies may help further define tumor subtypes and may potentially guide personalized (precision) medicine.

If your child has medulloblastoma, your child’s physician also will perform a lumbar puncture, or spinal tap. However, this will be performed at a time after the initial surgery is completed. In addition, there may be other diagnostic tests that your doctor will discuss with you.

Successfully treating your child’s medulloblastoma depends largely on whether the tumor can be completely removed through surgery and whether the tumor has spread to other parts of the brain or spinal cord. Typically, post-surgery medulloblastomas are divided into three risk assessment groups:

• infants (children under age 3)
• standard risk (no evidence of disease with a complete removal of the tumor)
• high risk (evidence of incomplete removal or tumor spread elsewhere in the nervous system)

Subtypes of Medulloblastoma:

Dana-Farber/Boston Children’s clinical researchers are involved in international collaborations that have revealed that medulloblastomas are comprised of at least four different subtypes. These include

• Wnt Medulloblastoma
• Sonic Hedgehog (SHH) Medulloblastoma
• Group 3 Medulloblastoma
• Group 4 Medulloblastoma

Each of these subtypes has a different biological driver, and some subtypes require more intensive treatments than others. These findings are guiding clinical trials exploring new treatments for children with medulloblastoma.

After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.

You and your family are key players in your child’s medical care. It’s important that you share your observations and ideas with your child’s health care provider and that you understand your doctor’s recommendations. If your child has been diagnosed with medulloblastoma, you probably have a lot on your mind. So it’s often helpful to write questions down. Some of the questions you may want to ask include:

• What does a diagnosis of medulloblastoma mean for my child?
• How will you manage my child’s symptoms?
• What are my child’s treatment options?
• How many other children with medulloblastoma does your team treat each year?
• What are the possible short and long-term complications of treatment?
• What is the long-term outlook for my child?
• How likely is it that the tumor will come back?
• What services are available to help my child and my family cope?

Coping and support

In addition to providing medical care, at Dana-Farber/Boston Children’s we strive to also meet all of your family's emotional and quality-of-life needs. We know that unfamiliar places, especially hospitals, often create anxiety and fear for a child. We also know this isn't an easy time or task for parents, who have their own fears and concerns about the situation. Our family support services will help address many of your needs and concerns. Read about our patient and family support services.

Your child's physician will determine a specific course of medulloblastoma treatment based on several factors, including: 

• your child's age, overall health and medical history
• type, location, and size of the tumor
• extent of the disease
• your child's tolerance for specific medications, procedures or therapies
• how your child's doctors expects the disease to behave?

There are a number of treatments we may recommend. Some of them help to treat the tumor while others are intended to address complications of the disease or side effects of the treatment.

In all cases, a multidisciplinary team is necessary to optimize care. The team may include members from neurosurgery, neuro-oncology, neurology, radiation oncology, and stem cell transplantation, as well as psychology/social work, nutrition, physical and occupational therapy, and the school liason program.

Treatment may include (alone or in combination):

Endoscopic third ventriculostomy (ETV) or ventriculo-peritoneal shunt (VP shunt): A tumor in the brain can cause blockage of cerebral spinal fluid, the fluid that bathes the brain and spinal cord. If this occurs, our pediatric neurosurgeons may perform a procedure to relieve symptoms of hydrocephalus, the build-up of fluid, which causes increased pressure within the skull.

In an endoscopic third ventriculostomy, surgeons create a small hole that allows fluid to flow around the blockage and into the spinal column. About 90 percent of children with symptoms of hydrocephalus will undergo this procedure.

In some cases, children may have an alternative procedure in which a tube is installed to drain excess fluid into the abdomen (VP shunt).

Surgery may be needed to treat hydrocephalus (fluid build-up in the skull) and to remove the tumor. Research has shown that the more completely the tumor is removed, the better the outcome may be. Therefore, your child's surgeon will remove as much of the tumor as safely as possible, while avoiding neurological side effects.

Radiation therapy uses high-energy waves from a specialized machine to damage or kill cancer cells and shrink tumors. Your child's physician will work with pediatric radiation oncologists to determine the optimal dose of radiation that will effectively treat the tumor while avoiding side effects as much as possible.

Chemotherapy is a group of drugs that interfere with the cancer cell's ability to grow. Different groups of chemotherapy drugs work in different ways to fight cancer cells and shrink tumors. Your child may receive chemotherapy:

• orally, as a pill to swallow
• intramuscularly, as an injection into the muscle or fat tissue
• intravenously, as a direct injection into the bloodstream; also called IV
• intrathecally, as a direct injection into the spinal column through a needle

What issues might arise after surgery?
After the operation, your child may have difficulties with coordination, weakness in his extremities and problems with balance. These typically resolve over a course of several weeks. Our physical and occupational therapists will work with your child to treat these issues.

"Posterior fossa mutism" is a condition that may occur after surgery. Within 24 hours, the child develops an inability to speak, has problems with balance and has difficulty with swallowing. The condition may range from mild to severe. The cause of this condition is not entirely known but it is unique to this area of the brain.
In about 15 percent of the children diagnosed with medulloblastoma, hydrocephalus may develop, requiring a procedure to drain spinal fluid. These procedures are performed by our pediatric neurosurgeons.

The prognosis (chance of recovery) and treatment options depend on:

• the tumor’s molecular subtype (the specific genetic mutations within the tumor)
• the age of your child at the time of diagnosis
• the location of the tumor
• the amount of tumor remaining after surgery
• whether the cancer has spread to other parts of the central nervous system (brain and spinal cord), or to other parts of the body, such as the bones

The outcome for children with medulloblastoma has improved dramatically over the past several decades.

The outcomes in infants remain poor and many studies are underway to evaluate new treatment strategies in infants. Some include aggressive chemotherapy, including high-dose chemotherapy and stem cell transplant, and localized radiation therapy to minimize the harmful effects of radiation therapy on the developing brain.

Long-term follow-up

Many children and adolescents diagnosed with medulloblastoma will survive into adulthood. However, survivors may face physical, psychological, social and intellectual challenges related to their treatment and will require ongoing assessment and specialized care.

To address the needs of this growing community of brain tumor survivors, Dana-Farber/Boston Children’s Cancer provides brain tumor survivorship support through the Stop & Shop Family Pediatric Neuro-Oncology Outcomes Clinic.

As a result of treatment, children may experience changes in intellectual and motor function. Among several programs addressing these needs are the School Liaison and Back to School Programs, which provide individualized services to ease children's return to school and maximize their ability to learn.

Children treated for a medulloblastoma should visit a survivorship clinic every year:

• to manage disease complications
• to be screened for early recurrence of tumor
• to manage late effects of treatment

We are conducting numerous research studies that will help clinicians better understand and treat medulloblastoma. Recently, scientists have discovered the molecular characteristics of medulloblastomas, identifying several subtypes, which may be correlated with prognosis. These discoveries are now helping researchers to develop better therapies. We now offer and are developing further clinical trials that target these specific subgroups.

Clinical trials

For many children with brain tumors or other rare or hard-to-treat conditions, clinical trials provide new options.

• Learn about our pediatric brain tumor clinical trials, including studies for innovative new therapies
• Get answers to common questions about clinical trials for cancer and blood disorders

Contact us: If you’re not sure which clinical trials might be right for your child, email us at clinicaltrials@danafarberbostonchildrens.org. We can help you navigate your options.