By Bill Thomas | May 8th
Of all the tools that doctors and patients have access to when facing the many challenges posed by pediatric cancers, few are as important or effective as knowledge. Knowledge is what allows us to understand how specific cancers work, and it’s what empowers us to develop and select the best possible treatment options for each individual patient.
It’s this power–the power of knowledge–that has motivated the Pediatric Cancer Research Foundation to invest more than $61 million in research that expands both our knowledge of pediatric cancers and our ability to treat them. Here at PCRF, our vision is to make it possible for all children facing childhood cancers to beat their disease and achieve their full potential so they can realize happy, healthy, productive futures. We believe that growing and sharing knowledge is one of the best ways to achieve this goal.
With that in mind, and because May is Brain Cancer Awareness Month, we’ve put together a helpful guide for patients, friends, family members, and anyone else interested in learning more about pediatric brain cancers. Below, we’ve outlined some of the most common types of pediatric brain cancers, what parts of the brain they affect, and the unique challenges they pose.
We hope that this guide will be helpful in spreading awareness of and sharing knowledge about pediatric brain cancers. The more that we know about pediatric brain cancers, the better we will be equipped to face the challenges they represent, not just on our own, but together.
5 Important Facts About Pediatric Brain Cancers
- Brain tumors are the most common solid cancers diagnosed in children aged 14 and under. They are also the leading cause of pediatric cancer-related death.
- More than 4,000 brain and spinal cord tumors are diagnosed annually in children and teenagers, with malignant tumors being slightly more common in male patients and benign tumors being slightly more common in female patients.
- Nearly three out of every four children with brain tumors survive at least five years after being diagnosed, although outlook varies greatly based on the tumor type and location.
- There are over 100 different types of tumors capable of developing in the brain or central nervous system. Primary cancers originate in the brain itself, while metastatic cancers originate in other parts of the body before spreading to the brain.
- Most pediatric brain tumors (roughly 60%) develop in the posterior fossa, at the base of the skull. The posterior fossa houses the cerebellum, pons, and medulla. These parts of the brain regulate vital functions such as breathing and cardiovascular activity, as well as motor memory and some cognitive functions.
What Are the Most Common Types of Pediatric Brain Cancers?
Although brain tumors overall are among the most common childhood cancers, there are many different types of brain tumors–more than 100, as noted above–with some being more common than others. Likewise, some pediatric brain tumors are more aggressive, making them more difficult to treat.
The following is a description of the most common brain tumors arising in children, and how they are approached for treatment.
Gliomas
Among the most common brain tumors diagnosed in all patients, regardless of age, are gliomas. Around half of all pediatric brain tumors are gliomas. These tumors originate in the glial cells that act as the support network for the brain’s neurons. Gliomas come in low-grade/slow-growing and high-grade/fast-growing varieties, and can be further broken down into various subtypes based on the tumor cell of origin, molecular characteristics, and biological properties:
- Astrocytomas are the most common form of pediatric brain tumor. In children, these tumors most typically arise in the posterior fossa, although may also arise in the cerebral hemispheres. Astrocytomas may also develop in the brain stem or along the optic nerves. Astrocytomas come in a number of varieties; low-grade pediatric astrocytomas have a five-year survival rate of around 90%, while high-grade gliomas (including diffuse intrinsic pontine gliomas, or DIPG) have a five-year survival rate of around 20%.
- Ependymomas are tumors that develop in the ependymal cells that line the fluid-filled cavities in the brain and central canal of the spinal cord. Ependymomas may be fast or slow-growing, but also tend recur following treatment. The five-year survival rate for children diagnosed with ependymomas depends on tumor location and molecular subtype, but overall is around 60%, with older children typically faring better than younger children.
- Glioblastomas form from cells called astrocytes that support nerve cells. Glioblastomas are Grade IV brain tumors, meaning that they are among the most aggressive and fastest-growing types of pediatric brain tumors. Their rapid growth often causes pressure in the brain and can quickly destroy healthy brain tissue. The five-year survival rate for children diagnosed with glioblastomas is 5%, with the average survival time being 12-18 months despite maximal treatment.
- Oligodendrogliomas are tumors that tend to form in the cerebral hemispheres, and are often the cause of new onset seizures. Although oligodendrogliomas can occur in patients of all ages, they tend to be more common in adults than in children, accounting for less than 1% of all brain tumors in children aged 14 and under. The five-year survival rate for children diagnosed with oligodendrogliomas is around 80-90%.
Medulloblastomas
Pediatric brain tumors may also arise from what are known as embryonal cells, which are residual cells from early brain development. The most common type of embryonal tumors are medulloblastomas, which most often develop in the cerebellum. The cerebellum is primarily responsible for muscle control, coordination, and balance, although it also plays a role in cognition, emotion, attention, and language.
Medulloblastomas account for around 20% of all pediatric brain tumors occurring in children, with an estimated 500 children diagnosed in the United States annually. Highly malignant, medulloblastomas grow rapidly and can quickly spread to other parts of the brain and the spinal cord. Most medulloblastomas require an aggressive treatment plan that may include radiation, chemotherapy, and surgery. However, there are molecular subtypes of medulloblastoma that are less aggressive and can result in good clinical outcomes.
Overall, the five-year survival rate for children diagnosed with pediatric medulloblastomas is around 70-80%. However, this is highly dependent on the extent of surgical resection, the molecular subtype of the tumor, and whether the tumor has already spread throughout the central nervous system at diagnosis. More intensive treatment is needed for tumors with a more aggressive subtype.
Craniopharyngioma
Although craniopharyngiomas are typically benign, the part of the brain where they occur–close to the pituitary gland, hypothalamus, and optic nerves–can be problematic, especially in the developing brains of young children.
As craniopharyngiomas grow, they may put pressure on sensitive structures within the brain, such as the nerves that help us see, or the glands which regulate our hormones. This, in turn, can lead to serious neurological and endocrine issues. Common side effects include headaches, nausea, difficulty sleeping, impaired vision, hormone dysfunction, and serious metabolic complications. While craniopharyngiomas are typically benign, in very rare cases, craniopharyngiomas may initially be malignant, or undergo malignant transformation. Unfortunately, even benign forms–up to 50% of tumors–tend to recur despite maximal treatment.
As a result, the five-year survival rate for children diagnosed with craniopharyngiomas reaches as high as 96% according to some estimates. Importantly, debilitating long-term health complications and quality of life issues can result both from the tumor itself as well as treatment modalities, making this type of tumor one of the most challenging to manage.
What Unique Challenges Do Pediatric Brain Cancers Pose?
It’s important to note that all forms of childhood cancer pose challenges to patients as well as their friends, families, and caregivers. Having said that, pediatric brain tumors are often especially dangerous and difficult to treat.
The biggest reason for this is because of how delicate the human brain is. Not only does the growth of tumors threaten structures within the brain, potentially leading to disruptions of potentially vital, life-sustaining physiological functions, but treatment options such as radiation, chemotherapy, and surgery are not without risk to the delicate and developing brain. Children with brain tumors are particularly vulnerable: as their brains and bodies are still growing and changing, disruptions to this complex developmental process could lead to significant long-term effects on growth, cognition, and function.
Another challenge in effectively treating pediatric brain tumors is the presence of the blood-brain barrier (BBB), a protective layer protecting the brain and spinal cord from the contents of the circulatory system. While the BBB protects the brain from contact with toxins or harmful substances that may arise in the bloodstream, it also poses an obstacle for the entry of chemotherapeutic agents into the brain tissue where it is needed to fight these tumors. Multiple efforts are underway to attempt to overcome this obstacle, including direct drug dosing to a tumor through a catheter, or the use of ultrasound waves to open the BBB, in order to improve drug delivery and efficacy for these deadly tumors.
As significant as these challenges are, however, we here at Pediatric Cancer Research Foundation believe that no obstacle is ever insurmountable. At this very moment, research teams all across the world are working to grow our knowledge of pediatric brain tumor biology, and create safer and more effective forms of pediatric brain tumor treatment.
What is the Future of Pediatric Brain Cancer Treatment?
As significant as the challenges outlined above are, we here at Pediatric Cancer Research Foundation believe that no obstacle is ever insurmountable. At this very moment, research teams all across the world are working to grow our knowledge of pediatric brain tumors and create newer, better, safer, and more effective forms of treatment.
PCRF is committed to powering research that accelerates cures and improves outcomes for patients diagnosed with pediatric brain tumors and other forms of childhood cancer. Here are some of the many exciting, innovative, and cutting-edge research projects currently receiving grant support from PCRF:
- Dr. Rintaro Hashizume at University of Alabama at Birmingham is exploring intranasal drug delivery to treat pediatric high-grade gliomas, an innovative and non-invasive method that bypasses the blood-brain barrier using the unique nerve connection between the nose and brain.
- Dr. Ashley Plant-Fox at Ann & Robert H. Lurie Children’s Hospital of Chicago is leading a phase I/II clinical trial focused on immunotherapies that activate T cells to target DIPG by presenting tumor markers.
- Dr. Angela Liou at Children’s Hospital of Philadelphia is studying how changes in gene regulation contribute to pediatric brain tumors, focusing on key mutations that may cause cancer in order to find potential targets for treatment.
- Dr. Gregory Friedman at University of Texas M.D. Anderson Cancer Center is exploring innovative immunotherapy using the genetically altered cold sore virus (HSV) “G207,” which has shown promise in transforming “cold” tumors into “hot” immune-active ones.
- Dr. Michelle Monje at Lucile Packard Children’s Hospital Stanford is accelerating research into high-grade gliomas and guiding the next generation of scientists towards pediatric brain cancer research by training postdoctoral fellows in her lab.
Thanks in part to grant funding from Pediatric Cancer Research Foundation, these researchers are pushing the boundaries of what’s possible, bringing us closer to better treatments and a future without pediatric brain tumors. If you would like to support our efforts to better the lives of pediatric cancer patients everywhere, please consider becoming a donor.
To stay up-to-date with all the latest news shaping the future of pediatric cancer treatment, don’t forget to follow Pediatric Cancer Research Foundation’s Profectus Blog!
