When someone close to you like – your Mum is sick, it can affect you in many ways. You might have a friend or relative stay with you while Mum is in hospital. You might have someone different taking you to school and making your lunch. While Mum is sick you might not be able to do things that you normally do, or you might do them with someone else.

Every person is made up of millions of cells. Cells are so tiny we need a microscope to see them. Every part of the body (bones, skin, muscle) has its own special types of cells. Each cell splits up into many cells. This makes us grow. Scratches and cuts on your skin heal because the cells in your skin split which makes more skin grow. This happens in every part of our bodies.

Cancer happens when cells split, and therefore grow, much faster than they should. These cells keep splitting to make a whole group of cells. This group of cells can also be called a lump, a growth or a tumour.

Cancer is not one illness. It is a word used to describe over 100 different illnesses. Even though doctors know a lot more about cancer now than they used to, they still don't know everything. They don't know what causes cancer and they are still trying to find better treatments. . We do know that there is nothing you could have done to make your Mum get cancer and that you can't 'catch' cancer like you can catch a cold. So it is OK to be close to your Mum while she is sick.

Once Mum knows she has cancer she may have to have treatment. Treatment is what the doctors do to make the cancer go away and make Mum well again. There are three main types of treatment for cancer. These are surgery, chemotherapy and radiotherapy. Your Mum may have one, two or all three of these treatments.

Surgery. Your Mum might have an operation to have the cancer taken out of her body. She might need to have chemotherapy and/or radiotherapy as well. . If Mum has an operation she may have to stay in hospital until she is well enough to come home. You might be able to visit her, see where she'll be sleeping and meet the new friends she has made.

Chemotherapy. Chemotherapy is when the doctors give Mum medicine that can destroy cancer cells. Sometimes chemotherapy is given before surgery, but usually it is given after surgery. Chemotherapy can stop cancer cells too small for the doctor to find before they get any bigger. These are called microscopic cells. A lot of people who have cancer have chemotherapy. The medicines used in chemotherapy can affect other parts of Mum's body. These effects are called side effects. This might include feeling sick and not being very hungry. It is also normal for people who have chemotherapy to lose some or all of their hair. Has your Mum lost any of her hair?

Radiotherapy. This is like having an x-ray, but the machine is much bigger. The radiation beam, like a sunbeam, goes straight to the spot where the cancer is, and can make the cancer shrink or even go away. Most people have lots of radiotherapy before this starts to happen, sometimes 30 or 40 times! This might be why Mum visits the hospital a lot. Radiotherapy does not hurt. You can't see or hear the x-ray beam either. You may be able to see a mark, which looks like sunburn, on the spot where the x-ray beam went into your Mum's body. Mum may have side effects to radiotherapy. Some side effects that your Mum might have could be that she feels sick and grumpy. This is because of her treatment, not because of anything anyone has done. .

It can be very different at home when Mum is sick or in hospital. You may be needed to help out around the house more than usual. Your Mum, and other people in your life, may be different from what they're normally like. They may be tired and grumpy. . Remember, it is nobody's fault that your Mum is sick. You might be able to help Mum while she feels sick. You could ask your Mum what jobs might help. You could make Mum a get well card.

Things that can help you. Sometimes it helps to talk about things that worry you. Maybe there's an adult that you trust who you could talk to?