What is a brain tumour?

A brain tumour is a collection of abnormal "cells" in the brain which are growing out of control. These cells were originally normal brain cells. For no good reason, they started to divide and make more of themselves. This growing collection of cells is called a "tumour." As the cells continue to make more of themselves, the "tumour" gets bigger and bigger, like bread baking. Since there is not a lot of extra room in the brain, the tumour may start to squish areas of the brain, causing them not to work properly.

Answered by Dr. Regina Jakacki, paediatric oncologist, Children's Hospital of Pittsburgh

How do you know if you have a brain tumour?

The signs and symptoms (fancy medical jargon for things you may feel or changes your body may show) depend on what part of the brain the tumour is growing in. Our brains are enclosed in a liquid called cerebrospinal fluid (CSF). This fluid is made deep inside your brain, flows down the spinal cord, then returns to the top of the brain. In kids, a growing brain tumour often blocks the normal flow of this fluid. The blockage can lead to headaches, vomiting, wobbliness when you walk, drowsiness and a whole bunch of other symptoms that just make people feel really sick.

Most importantly, nobody knows your body like you do. If something doesn't feel right, ask your folks or doctor about it. Brain tumours in kids are really rare, but trust yourself - if something doesn't feel right... check it out. It probably won't be a brain tumour, but it's important to get a checkup.

Answered by Dr. Stewart Goldman, paediatric oncologist, Children's Memorial Hospital, Chicago

Can you catch a tumour from someone else that has one?

No, you cannot catch a tumour from anyone else. Tumours cannot be spread from person to person. Most tumours occur because of changes in brain cells which make them grow faster than they should. The vast majority of brain tumours just happen, but do not run in families.

Answered by Dr. Herbert Fuchs, paediatric neurosurgeon, Duke University, Durham

What causes brain tumours?

All cells in our body have two tremendous qualities; #1) differentiation and #2) self-control. Brain tumours are caused by cells that lose these qualities.

"Differentiation" means cells grow up to have specific jobs. To explain this, think of when a single cell is fertilized and one cell becomes two, two cells become four, four become eight, etc. Somehow, over a nine-month period in the mother's womb, those cells get messages to become different from each other. As those cells grow they "differentiate" into different parts of the body. Some cells grow up to be part of the toe, others become part of the brain, or lungs, or skin. These cells have all taken on very specific jobs.

Cells also "regulate" themselves. This means they know when the body needs new cells, and they can reproduce themselves and know when to stop. This is what we call "self-regulation."

Tumour cells are cells that have lost the ability to differentiate and have lost their ability to regulate themselves. Tumour cells don't secrete evil substances; they don't chew up normal cells; they just grow monotonously in an undifferentiated way taking up space and causing pressure on normal structures.

Exactly what starts tumour cells to form and grow, we don't know, but we do know what doesn't cause tumours to grow. You don't get a brain tumour by eating the wrong foods, disobeying your family, or doing bad things. Some cancers, such as lung cancer, can be brought on by behaviours. If you smoke for 40 years, you can get lung cancer. Nothing like this occurs in brain tumours. The cause of brain tumours is actively being sought out by research scientists and this puzzle is being put together. But there is nothing that a family or child does to cause a brain tumour.

Answered by Dr. Stewart Goldman, paediatric oncologist, Children's Memorial Hospital, Chicago

What do the words "malignant" and "benign" mean?

A "malignant" brain tumour looks very different under the microscope than the normal part of the brain where it started. The more unusual the tumour cells look, the faster they usually divide and grow, and the more damaging they can be to normal areas of the brain. A malignant brain tumour grows into the normal areas of the brain so surgery cannot possibly remove all of it. Further treatment with chemotherapy and/or radiation is necessary to have the best chance of keeping the tumour from growing back.

"Benign" brain tumours usually look more like normal brain under the microscope. They usually grow and divide more slowly than malignant tumours. However, if their growth is not stopped, they can still cause a lot of damage. Some benign brain tumours can be treated with surgery alone, if the tumour is in an area where all the tumour can be removed without causing damage to important areas of the brain.

Answered by Dr. Regina Jakacki, paediatric oncologist, Children's Hospital of Pittsburgh

Why do people sometimes lose their hair when they take chemotherapy? Does it grow back?

Chemotherapy stops most cells from dividing and growing, including hair cells. While you are going through chemotherapy, the cells that make your hair and keep your hair attached to your head cannot do their job. Once you stop receiving chemotherapy, you hair will slowly begin to grow back, but it may be a different colour or have a different feeling than before your treatment.

Answered by Dr. Regina Jakacki, paediatric oncologist, Children's Hospital of Pittsburgh