While medulloblastoma is rare, it is the most common pediatric malignant (cancerous) brain tumor. Approximately 20% of childhood brain tumors are medulloblastomas. According to the American Cancer Society, about 500 children are diagnosed with medulloblastoma each year in the United States. There are four known subtypes of childhood medulloblastoma. The exact subtype can impact a patient’s treatment plan in some situations.
In adults, medulloblastoma represents only 1% of all malignant brain tumors. It typically affects younger adults (between 20 and 40 years of age). Only about 200 adults are diagnosed with medulloblastoma each year in the United States. Doctors have identified three subtypes of adult medulloblastoma. As with childhood medulloblastoma, different subtypes may call for different treatment plans.
Medulloblastomas start in the cerebellum, in the region of the brain at the base of the skull called the posterior fossa. This is the part of the brain that controls balance and other complex motor and cognitive functions. While medulloblastomas often grow quickly and can spread to other parts of the nervous system and the body, especially the bones or bone marrow, they usually respond well to treatment.
Medulloblastoma Risk Factors
Anything that increases the chance of developing medulloblastoma is a risk factor. Although the cause of medulloblastoma is not known, certain things may increase the risk.
- Age: Most medulloblastoma cases are diagnosed before age 16, and usually between the ages of 3 and 8. In adults, it is rarely seen after the age of 40.
- Gender: Medulloblastoma is more common in boys than girls. In adults, it is also more common in men than in women.
- Genetic conditions: People with cancer predisposition syndromes like Li-Fraumeni syndrome, Turcot syndrome and Nevoid basal cell carcinoma syndrome (Gorlin syndrome) are more likely to develop medulloblastoma. See our hereditary cancer syndromes page for more information.
In rare cases, medulloblastoma can be passed down from one generation to the next. Genetic counseling may be right for you. Visit our genetic testing page to learn more.