What are clinical trials?

Clinical trials research new treatments to see if they are more effective than the standard treatments already available. This may be testing a new drug,  researching different ways of carrying out an operation or a new way of giving a treatment. They involve current patients and aim to find the treatments that work best and cause the fewest side effects.

Treatment trials are the most common type of trial. They may be carried out to:

  • test new treatments, such as chemotherapy drugs, gene therapy or cancer vaccines
  • look at new combinations of existing treatments, or change the way they are given, to make them more effective or to reduce side effects
  • compare the effectiveness of drugs used to control symptoms
  • find out how cancer treatments work
  • see which treatments are the most cost effective.

There are also trials that look at improving prevention, screening, diagnosis and quality of life.

What are clinical trials?

Clinical trials are medical research trials involving patients. Patients take part in trials in all areas of medicine, not just in cancer and not just to test treatment. A clinical trial might also be used to compare different ways of diagnosing an illness, or it might test techniques for preventing a particular cancer.

Carrying out clinical trials is the only way to find out if a new approach to cancer care is better than the standard approach currently used. Without trials it would be very difficult to improve the prevention, screening, diagnosis and treatment of cancer. There would also be a risk that patients could be given treatments that could be harmful.

Trials are more commonly used with some cancers than with others. For example, there are often more trials for cancers that affect a lot of people, like breast cancer or bowel cancer, and fewer trials for rarer types of cancer, such as cancer of the pancreas.


Treatment trials

Treatment trials are the most common type of trial. In cancer care they may be carried out to:

  • test new treatments, such as new chemotherapy drugs and targeted therapies
  • look at new combinations of existing treatments, or change the way they are given, in order to make them more effective or to reduce side effects
  • compare the effectiveness of drugs used for symptom control
  • see which treatments are the most cost-effective
  • discover which treatments give fewer side effects
  • find out how cancer treatments work
  • see which treatments have the least impact on patients’ everyday lives.

Treatment trials are the only reliable way to find out if a different operation, type of chemotherapy, targeted therapy or radiotherapy, is better than what is already available. If doctors already knew that a new treatment was better than the standard treatment, there would be no need for a clinical trial and you would be offered it routinely as part of your care.

The treatment being tested might be aimed at:

  • improving the number of people cured (when the cancer doesn’t come back)
  • improving survival (how long people live after treatment)
  • relieving the symptoms of cancer
  • reducing 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 commonly used, such as tamoxifen or Herceptin® for breast cancer and paclitaxel for ovarian cancer.

Without ongoing clinical trials, it wouldn’t be possible to add to our knowledge about effective treatments.


Prevention trials

Prevention trials look at whether a specific treatment or other approaches, such as vitamins or diet, may help to prevent a specific type of cancer.


Screening trials

Screening trials look at new ways or methods of testing a person for a specific cancer. These trials are often aimed at detecting cancer early when the chance of cure may be highest.


Diagnostic trials

Diagnostic trials look at new ways to accurately identify a cancer and usually include people who may have symptoms of cancer.


Quality of life trials

Quality of life trials look at ways of improving a person’s sense of well-being. Many quality of life trials are combined with treatment trials because doctors want to know what effect a particular treatment is having on a person’s everyday life. They often include questionnaires, which are completed at different stages during the trial. These may assess the psychological and financial impact of the treatment on both patients and their carers, for example, whether someone has to take time off work to look after you while you have your cancer treatment.


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