A clinical trial is a research study designed to evaluate potential new treatment options. These studies are the result of a long and deliberate cancer research process that often takes years. Clinical trials test the safety and effectiveness of new or modified cancer drugs, new drug doses, unique approaches to surgery or radiation therapy, and varied combinations of treatments. Clinical trials play a central role in improving the treatment of medical conditions because they lead to higher standards of care. In the United States all new cancer treatment products must proceed through an orderly clinical trials evaluation process to ensure that they have an acceptable level of safety and demonstrate benefit to helping patients with a specific cancer before they become commercially available to other patients.

Clinical trials essentially fall into two general categories.

1. The first general category of clinical trials are designed to evaluate new drugs, compounds, or biologic agents that have not yet been approved by the Food and Drug Administration (FDA) for administration to patients. All substances must go through several phases of clinical trials to document their safety and effectiveness before the FDA approves them for routine use to treat cancer patients. Prior to FDA approval, these substances are only available through clinical trials; however, after FDA approval, they are commercially available.
2. Clinical trials may also evaluate drugs, compounds, or biologic agents already approved by the FDA for the treatment of one or more types of cancer. These substances have already been determined to be safe by the FDA and they are now being evaluated in different doses, schedules, and combinations to determine how to optimally use them for the treatment of a variety of cancers.