A cancer diagnosis often comes with a great deal of new information. As well as coping with the diagnosis there are a lot of new terms and statistics to understand. It is never easy.

It is fairly common for information about cancer to include statistics. Your doctors or nurses may use statistics, for example, to give you an idea how effective a treatment might be, or how likely you are to get a particular side effect from the treatment. Statistics can help us to make decisions about which treatments to have. However, unless your work involves dealing with statistics, you may have difficulty understanding what they mean.

Statistics is a way of presenting information in numbers. It is important to remember that statistics are usaully based on large numbers of people, who have taken part in cancer research trials. The statistics can't tell you what is going to happen for an individual person, although they can give you some idea and tell you what the 'chances are' of something happening, or not happening.

If you don't understand the statistics you have been given, ask your doctor or nurse to explain them again, possibly in a different way. You could also discuss them with one of the nurses on our cancer information service

If you are looking for information about cancer statistics, cancer Research UK have very detailed information about the incidence of cancer. All of their information about statistics is aimed at health professionals.

Why do cancers come back?

In some cases cancer can come back after treatment. It may come back in the same area in which it first started, this is known as a recurrence. This can happen because tiny cancer cells, that may have been left behind when the tumour was removed, or that weren't destroyed by treatments such as radiotherapy and chemotherapy, have begun to divide again and form a tumour.

it may develop in a different part of the body, often referred to as a metastasis or secondary cancer. This can happen because a cancer ous (malignant) tumour consists of cancer cells which have the ability to spread beyond the original site. If left untreated they may invade and destroy surrounding tissues. Sometimes cells break away from the original (primary) cancer and spread to other organs in the body by travelling in the bloodstream or lymphatic system. When these cells reach a new area of the body they may go on dividing and form a new tumour.