Brain tumors in children
June 8, 2020
Second only to leukemia, brain tumors are top of the list of common forms of cancer in children and the young. The German Brain Tumor Association says 25% of all cancer diagnoses in the young involve tumors in the brain and central nervous system. It's often kids at the age of six-and-a-half, and boys more often than girls.
Symptoms
The most common symptoms of a brain tumor are headaches, nausea and vomiting. Other symptoms include visual disorders, and balance and coordination issues.
That's true for children, as it is for adults.
But whether it's adults or children, the symptoms depend on where exactly a tumor is located in the brain. To find out, doctors use magnetic resonance imaging (MRI / MRT).
Doctors can learn a lot about a diagnosis by analyzing the layered images produced by an MRT. But they may also take a biopsy to confirm a diagnosis.
That involves taking a tissue sample and analyzing it under a microscope to discover whether the tumor is benign or malignant. A benign tumor is non-cancerous, it does not invade neighboring cells, whereas a malignant tumor is cancerous.
Everything changes
When a child is diagnosed with cancer it can hit them and their families hard. They have their entire lives ahead of them, but then everything changes. Instead of years of carefree childhood, they now face a life of operations, radiotherapy, chemotherapy or a combination of those and other measures.
It often starts with an operation to remove the tumor — hopefully, completely. Depending on the size and location of the tumor, neurosurgeons will open the cranium to perform a craniotomy.
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A craniotomy is a difficult operation that involves considerable risk — it can leave lasting damage. In contrast to other parts of the body, it's not always clear which parts of the brain control which function, even if surgeons are opening a skull and looking directly into a person's nerve center, as it were.
From relatively harmless to life-threatening
One of the most common brain tumors in children is an astrocytoma. An astrocytoma grows relatively slowly and can have various grades of seriousness. If surgeons are able to successfully remove an astrocytoma, there is a good chance of full recovery. The World Health Organization categorizes that form of brain tumor as Grade I.
More rare forms of cancer in children include medulloblastoma (WHO Grade IV) and ependymoma (WHO Grade II or III).
Ependymomas account for about 10% of all cases of brain tumor in children. "That can develop in the axis of the nervous system, affecting the brain as well as the spinal canal and spinal cord," says Kristian Pajtler.
Pajtler works at the Hopp Children's Cancer Center in Heidelberg (KITZ) as a specialist for ependymomas.
"That kind of tumor is relatively resistant to chemotherapy. That makes treatment difficult and presents doctors with big challenges, especially as many of the tumors develop recidivism," says Pajtler. "And the problem is you can't always repeat radiotherapy."
It may be possible to repeat radiotherapy once or twice, says the researcher, but that option is limited. What follows then, for instance, is chemotherapy. And that is a lot for a kid to handle.
Difficult decisions
Operations get very difficult when tumors are located in important parts of the brain. Those areas include regions that control speech and movement, or those near the brain stem.
"The brain stem is important for all kinds of functions, such as breathing. That makes it difficult to perform a radical operation. Doctors have to be very careful and balance the neurological damage they risk against saving a person's life, and whether the risk of damage is too great," says Pajtler.
Preschool-age kids can develop significant neurocognitive deficiencies that lead to learning difficulties. It may take longer for them to learn things and they can forget what they have learnt quicker than other kids. So, it's possible that those other kids will make fun of them. And that can be an extra burden for children with cancer.
No death sentence
A cancer diagnosis in children is not necessarily — what's termed colloquially — a death sentence. Pajtler says fatal cases are quite rare. If a surgeon can successfully remove a tumor, the chances of survival in children is about 75%.
"Among the more aggressive tumors, the survival chances are worse at about 40%. We try to develop various options for treatment in consultation with neurosurgeons and radiotherapists, but about 90% of patients in pediatric oncology receive a clearly standardized treatment," says Pajtler.
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Danger of a relapse
Pajtler says that in some cases an ependymoma can recur up to 10 times.
"That means the tumor is removed by operation, the children receive radiotherapy, and months or years later they have a relapse," he says, adding that the level or severity of the initial treatment is decisive here.
One of the most difficult procedures is the so-called R0 resection.
"That procedure aims to remove every last bit of a tumor, leaving no residual tumor cells," says Pajtler.
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Neurosurgeons and child cancer specialists need a lot of experience for an operation like that to be successful.
"So, we argue strongly for surgeons to carry out such operations only if they work in centers that see a lot of these tumor and where a lot of such operations are done," says Pajtler.
He says research, diagnosis and treatment should all take place at the same institute to ensure that new findings in research transfer quicker into treatment, and the other way around as well.
"That allows us to give children the most up-to-date treatment methods," Pajtler says.
It also gives researchers more access to clinical studies.
In the here and now
Living through operations, months of radiotherapy, chemotherapy, a constant sense of nausea, stomach pain, hair loss — it's hell. But kids can be very brave patients. They can live in the now, without worrying about yesterday or tomorrow. Pajtler says he sees it time and again.
"It's very interesting working with kids and also very nice," he says.
Pajtler says cancer treatments among kids are generally successful and recovery rates are relatively high, compared to those among adults. And kids make for very honest patients, too. "Their feedback can be very helpful, and also very tough," he says. "But when a child comes into the clinic and is happy to see you, that gives you a lot in return."