Cancer is the name given to a wide range of diseases that all work in a similar way. Body cells are constantly dying, but new cells grow and divide in your body all the time, keeping things ticking over and taking care of repair. A cancerous cell goes a little crazy – it’s different from normal cells and won’t stop growing. In some cases the cancer cells can spread to other parts of the body and grow there.
When a cancerous cell gets going, it makes more like itself. These usually form a cluster, and this growth is known as a malignant tumour. A malignant tumour is able to spread to and grow in other parts of the body. For example cells might break off and move somewhere else in your body, and start some trouble there.
Tumours can also be benign (almost always harmless). Benign tumours are unable to spread to other tissues and aren’t cancerous.
There are over 200 different types of cancer, and they all have different causes, symptoms and treatment. The four most common ones in the UK are breast, lung, large bowel and prostate cancer. These are responsible for over half of all new cancer cases. The good news is, treatments for cancer are very advanced nowadays. Survival rates have gone up nearly 20% in the last 20 years.