The Cochrane Cancer Network
URL: http://www.canet.org
Contact: Dr Chris Williams
The Cochrane Cancer Network was established to help organise Cochrane systematic reviews in cancer.
As cancer is such a large and complicated area involving different areas of the body and different therapies, it was felt that a single large Collaborative Review Group to cover all of cancer was impractical. The Network began functioning in February 1996 with the following aims:-
- Helping to develop Cochrane Collaborative Review Groups (CRGs) concerned with cancer
- Supporting the preparation, maintenance and dissemination of Cochrane systematic reviews in cancer
The Network is currently supported by a consortium of funders including Cancer Research UK, the Department of Health and Macmillan.
THE NEED FOR SYSTEMATIC REVIEWS IN CANCER
The principal objective of the Research and Development Strategy of the UK National Health Service (NHS) is "to create a knowledge-based health service in which clinical, managerial and policy decisions are based on sound information about research findings and scientific developments". This aim is shared by other health care systems internationally and high quality, up to date systematic reviews of randomised controlled trials of health care interventions are of key importance.
Why do we need systematic reviews in cancer?
The answer is two-fold. Firstly, there is so much information available that it is impossible for individuals to keep up with all the changes that are occurring in cancer care. For instance more than 20,000 bio-medical journals publish over 2 million articles in many languages each year.
Secondly, is a need to try to reduce the risk of bias as much as possible when analysing the published literature. The basic tool for clinical research is the randomised controlled trial, which was developed specifically to reduce the risk of bias. When we are assessing the evidence available from a series of randomised trials it only makes sense that this is done in such a way that we once again minimise the risk of bias creeping in.
For further information on why we need systematic reviews click here or look at the papers in the Cochrane Methodology Register on the Cochrane Library.
What is different about systematic reviews?
Traditionally experts in the field have written literature reviews in medicine. They may hold strong opinions, and have often not used objective methods designed to reduce the chances of bias. Systematic reviews try to reduce this risk by:
- Using an explicit detailed search strategy to find as many reports of relevant trials as possible
- Carrying out the review according to a written protocol
- Using explicit pre-specified inclusion/exclusion criteria
- Using standard methods to assess trial quality
- Employing two people to independently extract the data
- Analysing by synthesis of the actual numerical results, where possible, a technique known as meta-analysis
- Presenting the review in a detailed, clear and transparent fashion so that readers can see how conclusions were reached
Systematic reviews often give us the best estimate of what the results of all relevant trials mean. That does not mean to say that they can answer all our questions or be used as a recipe. However, systematic reviews can give us the best summary of current evidence that can be used when making individual treatment decisions or when designing new clinical trials.
