What is medulloblastoma?

Cancer starts when cells change (mutate) and grow out of control. The changed (abnormal) cells often grow to form a lump or mass called a tumor. Cancer cells can also grow into (invade) nearby areas. They can spread to other parts of the body, too. This is called metastasis.

Medulloblastoma is a rare type of brain cancer. It most often affects children. But in very rare cases, it can happen in adults. It usually affects adults between 20 and 40 years old. These tumors start in the cerebellum, which is near the lower back of the brain. The cerebellum controls movement, balance, and coordination.

Medulloblastoma is a primary brain tumor. This means it starts in brain cells. (It didn't start somewhere else in the body and then spread to the brain.) This type of tumor tends to grow quickly. It may spread (metastasize) within the brain and spinal cord. It can also spread to the bone marrow, bones, lungs, or other parts of the body, but this is rare. The outlook for tumors that have spread tends to be worse than for tumors that stay in one place.

Types of medulloblastomas

These tumors are grouped into 4 subgroups based on gene changes found in the cancer cells:

  • WNT (wingless). This is the least common subgroup.
  • SHH (sonic hedgehog). There are 4 SHH subtypes.
  • Group 3.There are 3 subtypes within this group.
  • Group 4. This is the most common subgroup.

Talk with your healthcare provider if you'd like to learn more about the medulloblastoma subgroup youare in and what the gene changes mean for your treatment and outlook.

What causes medulloblastoma?

A small number of people with medulloblastoma also have certain inherited disorders. These disorders increase their risk of getting these tumors, as well as other types of cancer.

These inherited disorders include:

  • Gorlin syndrome (also called nevoid basal cell carcinoma syndrome or NBCCS)
  • Turcot syndrome (a subtype of Lynch syndrome or familial adenomatous polyposis or FAP)
  • Cowden syndrome
  • Gardner syndrome
  • Li-Fraumeni syndrome

But many people who get medulloblastoma don't have one of these inherited disorders. It's unclear what causes most of these tumors.

Who is at risk for medulloblastoma?

Medulloblastoma is more common in children and young adults. In a few people with this condition, there's a link to an inherited disorder. But in most people, there's no known inherited risk. Researchers are actively trying to understand the genetics of medulloblastoma in hopes of better understanding the risk and possible treatments. The risk for medulloblastoma is higher in:

  • Children under age 8
  • People with certain inherited genetic disorders, such as those listed above
  • Boys compared to girls

What are the symptoms of medulloblastoma?

Symptoms of medulloblastoma may quickly get worse as the tumor grows. Sometimes a brain tumor may block the normal flow of cerebrospinal fluid (CSF), leading to increased intracranial pressure. This may cause headache, nausea, vomiting, and dizziness. Because the tumor is often in the cerebellum, it may affect balance and coordination early on.

Some of the general symptoms of medulloblastoma include:

  • Headaches (often tend to be worse in the morning)
  • Balance problems or clumsiness
  • Changes in thinking ability
  • Dizziness
  • Double vision or other eye problems
  • Tiredness and lack of energy (fatigue)
  • Nausea and vomiting
  • Hearing loss
  • Irritability and changed behavior

Many of these may be caused by other health problems. Still, it's important to see a healthcare provider if you have these symptoms. Only a healthcare provider can tell if you have cancer.

How is medulloblastoma diagnosed?

Your healthcare provider will ask you about your health history, your symptoms, risk factors, and family history of disease. A physical exam will be done, including a nervous system exam. Your provider may ask you to do simple things like walk, touch your finger to your nose, hold your hands out, or follow a light with your eyes. If theprovider thinks you may have a brain tumor, certain tests will be needed, such as:

  • MRI scan of the brain and spinal cord. MRIs use radio waves, magnets, and a computer to make detailed images of the inside of your body. For this test, you lie still on a narrow table as it passes through a long, tube-like scanner. The scanner sends beams of radio waves at the part of your body being scanned. A computer uses the radio waves to create a 3-D picture of your insides. You may need more than 1 set of images. Each 1 may take 2 to 15 minutes, so that the whole scan may take an hour or more. A contrast dye might be put into a vein in your hand or arm before this scan. It helps get even clearer images of the inside of your body. You might be given earplugs because there's loud thumping and buzzing noises during the scan. If you're not comfortable in small spaces (claustrophobic), you may need to be given a sedative before having this test.
  • Biopsy. A biopsy is the only sure way to know what kind of tumor you have. A biopsy can also show if the tumor is a primary or secondary brain cancer. (A secondary brain cancer is one that has spread to the brain from cancer that started in another part of the body.) Surgery is done to take out tiny pieces of the tumor. The pieces are sent for testing right away. If cancer is found, the healthcare provider may try to remove as much of the tumor as possible during the same surgery.
  • Spinal tap (lumbar puncture). To do this, a very thin needle is put through the space between the bones of your lower spine and slid into the space around your spinal cord. A small amount of the fluid there (called the CSF or cerebrospinal fluid) is then removed to check it for tumor cells.

You may first see your primary healthcare provider. If a brain tumor is suspected, your providerwill likely refer you to a healthcare provider that deals with brain disorders. This might be a:

  • Neurologist. This specialist diagnoses and treats brain and spinal cord diseases.
  • Neurosurgeon. This is a specialist who does brain or spinal cord surgery.
  • Neuro-oncologist. This is a specialist in brain and spinal cord cancers.

How is medulloblastoma treated?

Depending on the type of brain tumor and where it is, your healthcare team will decide the best treatment plan for you. The main treatment is surgery to remove as much of the tumor as possible. Fully removing the tumor increases the chances of a good outcome. After surgery,radiation therapy and, in some cases, chemotherapy, might also be needed.

Depending on the tumor characteristics and the age of the person with medulloblastoma, 1 or more of thesetreatments might be used:

  • Surgery to remove as much of the tumor as possible (often the main treatment)
  • Radiation therapy to the entire brain and spinal cord, with focused radiation on the spot where the tumor was (This might not be used in children under age 3.)
  • Chemotherapy (often after radiation)

Sometimes a tumor blocks the flow of CSF (cerebrospinal) fluid around the brain. This causes an increase in intracranial pressure (ICP), which can lead to things like headaches, nausea, vision changes, and brain damage. If yourICP is high, a thin, flexible tube called a shunt may be needed. Surgery is done to place the shunt so that it drains the excess fluid away from the brain and into the abdomen (belly) or, less often, the heart. This lowers the intracranial pressure. A shunt may be short-term or permanent.

You will work closely with your medical team to decide on the best treatment plan for you.

What are the possible complications of medulloblastoma?

Many people with medulloblastoma have good outcomes. Still, the treatments used can damage normal cells and cause side effects. Your healthcare provider will talk with you about side effects linked with your treatment. Ask when and how to report side effects to your healthcare team. There are often ways to manage side effects. And there may be things you can do and medicines you can take to help prevent or control many treatment side effects. Ask how to reach your healthcare team during evenings, weekends, and holidays.

Some people have complications due to the surgery or other treatments. In some cases, the tumor comes back (recurs) after treatment. To watch for recurrence, you'll likely need follow-up MRI scans in the weeks after surgery and then a few times a year after that.

Possible complicationscan include:

  • Nausea, vomiting, and fatigue, due to radiation therapy or chemotherapy
  • Fertility problems, due to radiation therapy or chemotherapy
  • Recurrent tumor
  • Cognitive changes
  • Increased risk for other kinds of cancer later in adulthood
  • Damage to other organs, like the heart, thyroid, muscles, or bones

Talk with your healthcare provider about the risk of treatment complications (both short- and long-term), your overall outlook (prognosis), and the chances of the tumor coming back.

Key points about medulloblastoma

  • Medulloblastoma is the most common brain cancer in children. It's rare in adults.
  • These tumors start in the cerebellum, the part of the brain that controls balance and coordination.
  • Symptoms often include headache, nausea, and vomiting. These tend to be worse in the morning.
  • Surgery is usually done to remove as much of the tumor as possible.
  • Radiation therapy and chemotherapy are sometimes used after surgery.

Next steps

Tips to help you get the most from a visit to the healthcare provider:

  • Know the reason for the visit and what you want to happen.
  • Before the visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what theprovider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new directions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help. Also know what the side effects are.
  • Ask if yourcondition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if the medicine isn't used or the test or procedure isn't done.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact thehealthcare provider if you have questions or need to report worrisome signs or symptoms.