Types of Clinical Trials
Types of Clinical Trials

The goal of a clinical trial determines what type it is

Some examples of the goals of clinical trials are:

  • Prevent cancer
  • Diagnose cancer
  • Treat cancer
  • Help cancer patients, their families and loved ones manage the experience of having cancer.
Prevention trials
Many different ways of preventing cancer are studied in cancer prevention trials. Such as:
  • Medicines
  • Vitamins
  • Minerals
  • Other supplements
  • Exercise
  • Diet
  • Changing behaviors

Example: The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is looking at whether taking Selenium (a mineral) and vitamin E will reduce the chances of getting prostate cancer.

Early Detection Trials
Also known as Screening Trials - these studies look at ways to find cancer before symptoms appear. Some possible screening methods include:

  • Imaging such as X-rays, MRIs or ultrasounds.
  • Tests to find signs of cancer in the blood.
  • Physical exams

Example: The National Lung Screening Trial (NLST) is comparing chest X-rays with another imaging method called spiral CT to see which method is better at finding lung cancer early in people who are at high risk because of heavy smoking.

Treatment Trials
These studies are designed to find more effective treatments for cancer. These studies compare a new treatment with treatments that are being used now.
Possible new treatments include:

  • New chemical substances (newly developed molecules).
  • A new way of using a known treatment for cancer.
  • A new way to use medicines used for other diseases or problems.

Example: Thalidomide was used in Europe to prevent miscarriages in the 1950s. It turned out to cause birth defects because it interfered with the normal development of blood vessels (development of arteries and veins is called angiogenesis). Thalidomide is now used to interfere with the development of blood vessels (anti-angiogenesis) that feed cancerous tumors.

Quality of Life Trials
These studies are designed to find better ways to manage cancer treatments and cancer-related side effects. Some possible Quality of Life questions that these studies try to answer include:

  • Does a medication typically used for another medical purpose help reduce cancer patient fatigue?
  • Does biofeedback help the patient cope with depression?
  • What impact do cancer therapies have on the patient and the family.

Note: Most trials now include evaluation of quality of life (even for people who are not doing well).

Example: A study conducted to evaluate the use of acupressure to reduce nausea and vomiting in patients taking chemotherapy.





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