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About statistics

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This page tells you about statistics. There is information on


Whether statistics are reliable

Many people do not trust statistics. They think that statistics can be made to 'say' whatever anyone wants.

To some extent, it is true that you can manipulate statistics to fit what you want to say. But only if you are deliberately trying to change the figures to suit yourself. For example, if you are trying to sell a product, you will pick the statistics that show your product to be the best thing since sliced bread! You won't print the statistics that said half the people who had bought it thought it was rubbish!

Researchers and cancer doctors are not trying to fiddle the figures. They are genuinely interested in finding answers to the questions they need to ask. For example, which treatment works best?

But the answers you get from statistics still depend on the questions you ask. Will the answers to these questions be the same?

  • Which treatment works best?
  • Which treatment is most cost effective?

They won't necessarily be the same answer. The more cost effective treatment may put more cancers in remission per £100 spent just because it is cheaper. It is important to carefully read the question being asked when you are looking at statistics of any sort.


What statistics can tell you

Understanding statistics can be very important if you are trying to find out about new cancer treatments or looking into other treatment options. Statistics can tell you whether one treatment is likely to work better than another for a particular type of cancer. There is more about this in the page about looking at research in this section of CancerHelp UK.

Understanding statistics a little better can help you to understand more about what your doctor tells you too. Many different statistics are collected about cancer and treatments. We can help you to know what the statistics mean on our page explaining incidence, survival and mortality statistics in this section of CancerHelp UK.


What statistics can't tell you

Statistics can't tell you exactly what will happen to you personally. They are general information that apply to a group or 'population' of people from which the statistics were calculated. This could be tens, hundreds or thousands of people. Statistics may be able to tell you what the chances of something happening to you are. For example, if 65% of people with your type of cancer responded to a treatment, then there is a two out of three chance that you will too. But no one can say definitely whether your cancer will respond to that treatment.

Statistics cannot usually fit your situation exactly. They are usually much more general than people think they are. A patient may ask her doctor, "What are the survival statistics for someone with a grade 3, stage 2 breast cancer who has had a lumpectomy, 6 weeks of radiotherapy, 6 months of CMF chemotherapy and has been on tamoxifen for 2 years?". Statistics in that sort of detail just don't exist. The statistics available are usually for a cancer type, although sometimes they are available for different stages of a cancer.

Individual research studies will have produced statistics on bits of that scenario. For example, researchers have shown that pre-menopausal women who have a course of chemotherapy after surgery have a lower chance of their breast cancer coming back.

To produce the sort of detail the patient above asked for, you would have to find several hundred women in that exact situation to test the chemotherapy on, and then follow their progress for some years, to see how they did. And even then, you would only get generalised statistics, because they would probably have several different types of breast cancer. And they may well have had radiotherapy in different ways, or at different doses. And are they oestrogen receptor positive? How old are they? Are they pre or post menopausal? So, no situation is as straightforward as it might appear.

You and your situation are unique. As there is no one else quite like you, then no statistics are able to give you exact answers about the outcome of your particular cancer. But statistics can be used by you and your doctor to help choose which treatments are most likely to benefit you. Some doctors use computer programs that use statistics in this way. One that you might hear mentioned is called Adjuvant! Online. The computer programme compares the results of many trials.

So, using computer programmes doctors can get some information about the effectiveness of different types of treatment in some situations.

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Updated: 29 August 2013