While scientists don’t know for sure how brain cancer in children occurs, it is likely to be associated with genetic or cellular mistakes that don’t get erased naturally. — Positive Parenting
The odds that a doctor will diagnose your child with paediatric cancer are slim, and the chances of a brain cancer diagnosis are even smaller.
Paediatric brain cancer is so rare that doctors and researchers are still learning why it occurs.
Paediatrician and Children’s Hospital of Philadelphia Cancer Predisposition Program director Dr Garrett Brodeur answers some questions about what causes cancers in kids, and why some may be more vulnerable than others.
We don’t know for sure.
I would say we have a good suspicion that it has to do with mistakes made as cells are multiplying during development, either prenatally or postnatally.
When a person is conceived, they’re one cell, one fertilised egg.
And when they’re born, they’re 10 trillion cells.
Each time one cell becomes two, it has to copy six billion base pairs of DNA (deoxyribonucleic acid) exactly.
It’s a very complicated process.
When mistakes happen, those cells end up dying most of the time.
They end up not being able to survive, either because the mistakes may cause the cells to die, or there are other protective mechanisms that recognise that something’s wrong and internally activate a self-destruct mechanism, or cellular suicide.
But it doesn’t always happen.
A cell may get some growth advantage and it doesn’t die.
And that’s probably what causes most childhood cancers of the brain or elsewhere.
We know that some patients are genetically predisposed to get their cancer, because they have a mutation in a gene that puts them at increased risk.
Sometimes, that increased risk is very high compared to the general population.
There are really just two ways.
One way is there’s a family history of a certain cancer, or group of cancers, that tend to go together related to a syndrome.
The second way is they have physical features of that syndrome.
For instance, there’s a syndrome where you get thyroid cancer and a lot of those patients – but not all – will have a very large head.
We biopsy tumours and see what it’s like under the microscope to make the diagnosis, then we genetically analyse the tumour itself.
So, virtually every tumour has some, or in many cases, a lot of genetic changes.
When we look at the changes in the tumour, sometimes we’ll see a change in a gene that we know – if it were in all the cells of the body – that would have predisposed them to get that cancer.
The main thing we can offer right now is surveillance.
So if we know what type of tumour they’re likely to get, we can do tests, whether it’s a physical exam, blood tests, ultrasounds, MRI (magnetic resonance imaging), X-rays or whatever.
We can do tests to try and identify the tumour when it’s small and when it’s easy to remove surgically.
Then they usually don’t need radiation, and very little chemotherapy.
It’s usually not spread throughout the body and they have a very good prognosis.
So, if we know someone has an increased risk for a brain tumour, we can do MRIs of the brain every six months or a year.
The general signs are headache, vomiting and abnormal eye movements caused by paralysis or impairment of some of the cranial nerves that control the eye muscles – By Wendy Ruderman/The Philadelphia Inquirer/Tribune News Service
