Pediatric Brain Tumors


Introduction:

Tumors. Just the word can send chills up your spine. My grandfather was diagnosed with
a brain tumor in his late 60's and the doctors thought their was little chance of survival. My next door neighbor was diagnosed with a brain tumor at the age of 4 and the doctors again thought there was little chance of survival. My grandfather lived, my neighbor didn't.
How could this happen, why could the doctors save one person but not the other I would always ask myself? From then on I knew I wanted to work in the field of neurology to try to answer these questions, and to help people affected by brain tumors, specifically children. Brain tumors affect nearly 1,500 to 2,000 children in the U.S. every year[1] . Brain stem gliomas, teratoid/rhabdoid and glioblastoma multiforme have survival rates of less then 20%[2] , and as many as 69% of children will survive, but they are often left with long-term side effects[3] .


What Causes Brain Tumors:

Genetics, environment, genetics and environment, or random, one of these four explains why brain tumors exist, but which one is it? For adults it would be fisable that genes and enviroment play a role in brain tumors, but children are not exposed to the enviroment for long periods of time before a tumors develops. Could this mean that children's brain tumors must completely stem from mutaed of missing genes? This is what Dr. Paul G. Fisher, MD Associate Professor of Neurology and Pediatics at Stanford University, believes. He believes that the mutated glial cells (cells that support and nourish the brain) go through rapid mitosis to form a malignant tumor [4]


Diagnosis:

I) Signs and Symptoms: Headaches, vomiting, siezures, loss of balance, lack of coordination, double vision, difficulty speaking and more. The
signs are directly linked to where the tumor is in the brain.


II) Tumor Grade: If the tumor is malignant then the doctors assign the tumor a rating based on the abnormality of cancer cells and
their differentiation. After the tumor is graded based on this general scale it is then graded specific to the type
of cancer [5] .

Grade I- Is a low-grade tumor. Grade I tumors are usually the least aggressive
Grade II- Is a low-grade tumor
Grade III- Is a high-grade tumor
Grade IV- is the highest-grade tumor, and the most malignant.




Types of Tumors Specific To Children
Types of Tumors Specific To Children





Types of Brain Tumors Specific To Children:


  • Neuroblastoma: Neuroblastoma is a cancer of specialized nerve cells, called neural crest cells. These cells are involved in the development of the nervous system and other tissues. The average age at diagnosis is about 18 months of age but it is occasionally seen in teenagers [6] .
  • Medullablastoma- This is the most common malignant brain tumor in children and accounts for 10- 20% of pediatric brain tumors[7] . This tumor almost always grows in the middle of the cerebellum, which makes it hard to surgically remove from the brain. Often times medullablastoma's have to be treated with radiation or chemotherapy in attempts of removing to tumor.

  • Atypical Teratoid-Rhabdoid tumors (ATRT): Are highly aggressive tumors that occur mostly in children younger then 2. Atypical teratoid/rhabdoid tumor may be linked to a change in a tumor suppressor gene called INI1, which is gene that helps make a protien critical to cell growth. [8] .

  • Gliomas: (tumor that arises from glial cells in the brain and spinal chord and accounts for 44.4% of all tumors)

Astrocytomas: Astrocytomas are the second most common brain tumor seen in children, and can occur in most parts of the brain. However Astrocytomas in the base of the brain are more common in children. [9]
Astrocytomas.jpg
Astrocytoma

Grade I- Are low grade Astrocytomes. They are generally curable and can be surgically removed.
Grade II- Are low grade Astrocytomas. This type of tumors is generally located in the posterior
fossa.
Grade III- Are high grade Astrocytoms. Children diagnosed with grade III astrocytomas usually
only survive on average for about 18 months while simultaneously being treatmented by
chemotherapy and radiation.
Grade IV- Are high grade Astrocytomes refered to as Glioblastoma Multiforme. Glioblastoma is the most common cancer of the Nervous System and second most frequent brain
tumor[10] . A study by Bondy in 1994 showed that 80% of patients with this type of
tumor had more than one copy of chromosome seven[11] .


Ogliodendrogliomas: Ogliodendrogliomas Tumors are virtually incurable. They are
thought to arise from the cells that insulate the axons in the axon
terminal, and typically occur mainly in the frontal lobe [12] . The median survival from initial diagnosis of all low-grade oligodendrogliomas is 4-10 years, but it is only 3-4 years for anaplastic oligodendrogliomas (Grade III) [13] . It is thought that Ogliodendroglima may arise as a result of a deletion of of 1p of 12 on the chromosome[14] .


Normal Tissue
Normal Tissue

Abnormal Oligodendroglioma Tissue
Abnormal Oligodendroglioma Tissue


Ependymomas: Ependymoma Tumors are located in the ventricles of the brain
Ependymoma
Ependymoma
and
obstruct the flow of cerebrospinal fluid. These tumors tend to grow very slow in the posterior fossa [15] .
Grade I – Myxo-papillary ependymoma and sub-ependymoma
Grade II – Ependymoma (low-grade)
Grade III – Anaplastic (malignant) ependymoma.





Treatment:

Treatment is dependent on the type of brain tumor the child has. There are over 120 different types of brain tumors, which make effective treatment complicated[16] . Often times surgeons will first try to remove the tumor, but this is very risky for some tumors because of where it is proriferating in the brain. Whether removing the tumors is successful or not the doctors next resort to procedures such as radiation and chemotherapy

  • Radiation- Radiation is a therapy that doctors try to be avoid with child patient. Because children are just begging to develop direct high-dose X-rays that help to kill the tumor cells often times damage the brain and prevents development. Pediatric doctors usually reccomend this as a last resort and to wait till the child grows to and older age because of the complications that are associated. If a doctor finds that this is a good choice of treatment the child is usually given it daily for 6 - 8 weeks[17] .

  • Proton Beam Radiation- Proton Beam Therapy is one of the newer therapy's doctors are experimenting with to help treat cancer. It is a type of radiation, but is thought to be much safer then the typical radiation because of the different rays it is emitting. Watch the movie above to see details on this state of the art, late breaking technology.


  • Chemotherapy- Chemotherapy is required for the more aggresive brain tumors. It is a treatment that uses chemicals intended to kill rapidly dividing cells/ cancer cells. Although this is beneficial in killing the abnormal growing cancer cells it also kills cells of the bone marrow, hair follicles, and digestive tract resulting in undesirable side affects [18] .

Social and Ethical Implications:

In a general sense, it is hard to say there are any social and ethical implications, but when one looks at research and therapies involved with pediatric tumors thats when these implications are arise. First off experimenting on children is a very controversial topic. Some may argue that it is unethical to experiment on children that have brain tumors, which I would disagree with. I think research is the primary way children in the future affected with these brain tumors are going to be helped. Gene therapy is another ethical problem associated with pediatric brain tumors, for example the big controversy doctors were trying to treat two boys that had a brain disease with the deadly HIV virus.

Article: Two Young Children With Brain Disease Being Treated With The HIV/AID's Virus

Future of Childhood Brain Tumors:

Science and technology are both advancing at a ten fold, yet brain tumors in general are still only understood to a certain degree. Hopefully, as science and technology advances there will be significant findings on detection and therapy of pediatric brain tumors to help these patients who are innocently suffering from such a morbid health issue. Perhaps if Dr. John F. Fisher's hypothesis is correct that pediatric brain tumors are purely associated with genes, then society will one day be able to find a therapeutic way to reverse specific genes in a child in order to prevent brain tumors. Although this all sounds like a wonderful idea there is still extensive research to be done to reach this point.

Here is a link to patient stories that survived and died during their battle with brain cancer: http://www.stjude.org/stjude/v/index.jsp?vgnextoid=1cebbfe82e118010VgnVCM1000000e2015acRCRD
  1. ^ http://www.mdanderson.org/patient-and-cancer-information/cancer-information/cancer-types/childhood-brain-tumors/index.html?cmpid=google_child_brain_tumor_ppc&gclid=CNK1053l46ECFch_5QodA3YOIQ
  2. ^ http://www.pbtfus.org/medcomm/research/Pediatric-brain-tumor-facts-updated.html
  3. ^ http://www.google.com/imgres?imgurl=http:www.sdbtf.org/images/pie-chart.jpg&imgrefurl=http://www.sdbtf.org/facts-bout-bt.html&usg=__SfOPbEsweuxEBwxYexRax_xbYT0=&h=335&w=432&sz=57&hl=en&start=1&um=1&itbs=1&tbnid=JK7KcdH6hE66aM:&tbnh=98&tbnw=126&prev=/images%3Fq%3Dpediatric%2Bbrain%2Btumor%2Bsurvival%2Brate%26um%3D1%26hl%3Den%26tbs%3Disch:1
  4. ^ Type your reference here.
  5. ^ http://www.cancertreatmentwatch.org/general/grading.shtml
  6. ^ http://www.macmillan.org.uk/cancerinformation/cancertypes/childrenscancers/typesofchildrenscancers/neuroblastoma.aspx

  7. ^ http://www.mayoclinic.org/pediatric-brain-tumors/types.html
  8. ^ http://www.stjude.org/stjude/v/index.jsp?vgnextoid=5efc061585f70110VgnVCM1000001e0215acRCRD&vgnextchannel=b4dcbfe82e118010VgnVCM1000000e2015acRCRD
  9. ^ http://www.mayoclinic.org/glioma/astrocytomas.html
  10. ^ http://en.wikipedia.org/wiki/Astrocytoma
  11. ^ http://brain.oxfordjournals.org/cgi/content/full/130/10/2596
  12. ^ http://en.wikipedia.org/wiki/Oligodendrocytes
  13. ^ http://emedicine.medscape.com/article/1156699-overview
  14. ^ http://www.braintumor.org/Oligodendroglioma/
  15. ^ http://www.childhoodbraintumor.org/index.php/brain-tumor-types-and-imaging/98-ependymomas.html
  16. ^ http://www.wyliesday.org/?page_id=2
  17. ^ http://www.mdanderson.org/patient-and-cancer-information/cancer-information/cancer-types/childhood-brain-tumors/index.html?cmpid=google_child_brain_tumor_ppc&gclid=CObbg52j8KECFQuB5QodpzGJLg
  18. ^ http://www.medicinenet.com/chemotherapy/article.htm