How common is medulloblastoma??

Currently, it is estimated that around 500 children are diagnosed with medulloblastoma annually in the United States. It is the most common malignant brain tumor in childhood, making up about 20% of all tumors of the central nervous system in children under the age of 19. It very rarely occurs after a person is in their 40s (70% of all cases are diagnosed before the age of 10). The highest rates of this tumor occur in children between the ages of 5 and 19. This type of tumor exclusively occurs in the cerebellum. In 2-5% of cases, there are some genetic mutations at play that increase the risk of a child developing medulloblastoma. It has also been found to be more common in males than in females.

One study, from 1984, analyzed epidemiological trends in medulloblastoma cases in children. This study looked at 143 children ages 19 and under with a diagnosis of medulloblastoma. They found the average age of diagnosis in these children was 6.5years-old. All of the patients in study received a variety of treatments, with the majority receiving some form of both surgery and irradiation. They analyzed the probably of survival in the patients they were studying and found: 0.687 probability within 6 months, 0.444 probability within 1 year, and 0.314 probability within 2 years. It is important to remember that this study is more than 30 years old and, therefore, the numbers may not be as accurate as more recent studies. However, this large epidemiological study did help pave the way for others to begin to understand the rates and prognosis of medulloblastoma in children.

A more recent study from 2015 analyzed the incidences of a variety of brain cancers in children under the age of 2. This study looked at a group of 32 patients and found that medulloblastoma tumors made up 18.8% of the tumors (6 out of the 32 patients). Interestingly, they found that, for any brain tumor, those children who treated it more aggressively with surgical tumor resection had an average survival time post-surgery of 67.6 months. On the other hand, patients who were more conservative with their treatment and using medications as their main form of treatment had an average survival time of 25.3 months after starting the medication regimen. An even more conservative form of treatment was undergone by some members of this study. This involved some medication and ventriculoperitoneal shunting to help reduce intracranial pressure. This group had a mean survival time of 10.5 months after beginning their treatment plan.

When reading large studies like these, it is very easy to get overwhelmed and lost in all of the numbers and scientific terms. As I continued to scroll through multiple studies, with multiple numbers flitting past my eyes for how frequently this type of tumor occurs and how long most children survive, it was very difficult to maintain a positive attitude. While it is understandable to want to understand and know everything you possibly can about the diagnosis, I think it is very important to remember that every human life is worth so much more than a number in a study. Take all of these numbers with a grain of salt and recognize that every single patient will have a unique experience and outcome. There aren't a lot of rules on The Road to Awesome, but one of the most important rules it to always, always, always, try to stay positive.

References:

http://www.uptodate.com/contents/clinical-presentation-diagnosis-and-risk-stratification-of-medulloblastoma

http://www.abta.org/brain-tumor-information/types-of-tumors/medulloblastoma.html

Yu, J., Shi, W., Zhao, R., Gao, X., & Li, H. (2015). Epidemiology of brain tumors in children aged two and under: A 10-year single-institute study. Oncology Letters, 9, 1651-1656.

Farwell, J., Dohrmann, G., & Flannery, J. (1984). Medulloblastoma in childhood: An epidemiological study. Journal of Neurosurgery, 657-664.