What are the different stages of Cancer?

Kat - There are lots and lots of different types of cancer. People say the word "cancer" but it's actually many, many different types of disease and as we've heard today, they're all very different.

It depends what genes have gone wrong in them, it depends what type of tissue in the body they started in, and doctors tend to stage cancer according to how far it's spread.

Normally, a cancer will start when a cell starts multiplying out of control. We think about cancers not just as a little clump of cells that have gone wrong, but really as a rogue organ - so it's starting to grow a blood supply, and it's starting to involve immune cells and cells from the tissue around it - that's kind of very early stage cancer. And if you can catch cancer at that kind of stage, it is very easy to remove with an operation and that the person will get better again. This is why it's so important to try and catch cancer early, to go to the doctor if there's something wrong, if it doesn't feel right, because in many cases, early stage cancer can be successfully cured with surgery. Then you start to look at the later stage, when it starts to spread. It spreads through the lymph nodes in the body or starts to spread through the bloodstream. And so, that can be really difficult to treat.