Why clinical trials are needed

In cancer, clinical trials are most commonly used to:

• try out new forms of treatment such as surgery, radiotherapy or chemotherapy
• control symptoms, such as pain and sickness
• test the effectiveness of psychological therapy.

The treatment being tested may be aimed at:

• improving the number of people cured - (where the cancer doesn't come back)
• improving survival - (how long people live before the cancer comes back)
• relieving symptoms of the cancer
• relieving the side effects of treatment
• improving the quality of life or sense of well-being for people with cancer.

Many drugs that have been tested in clinical trials are now in common use, such as tamoxifen for breast cancer and cisplatin for testicular cancer. Without ongoing clinical trials it would not be possible to add to our knowledge about effective treatments.

Once trials have shown that a treatment is effective, further trials are often carried out to find better ways of using it. These trials may include giving it in different doses or combining it with other treatments. For example, a few years ago a trial showed that people with lung cancer who had chest symptoms could be treated just as effectively with two sessions of radiotherapy as with 10 sessions. This discovery has made the treatment much more convenient for patients.

Clinical trials also play a valuable role in testing ways of helping people cope with the emotional aspects of cancer.