About Cancer Clinical Trials

Image of three Mayo Clinic doctors collaborating on clinical trials.

Cancer clinical trials help physician-scientists at Mayo Clinic find new and better ways to control and treat cancer.

During a clinical trial, participants receive specific interventions and researchers determine if those interventions are safe and effective. Interventions studied in clinical trials might be new cancer drugs or new combinations of drugs, new medical procedures, new surgical techniques or devices, new ways to use existing treatments, and even lifestyle or behavior changes.

For a new cancer treatment to become standard, it usually goes through two or three phases of a clinical trial. The early phases of cancer clinical trials are designed to study the safety of the new treatment. Later phases determine the effectiveness of the new treatment while continuing to study its safety.

Phase I clinical trials

The goals of a phase I clinical trial, also called an early-phase clinical trial, are to determine safe dosage levels and safe methods of delivering a new treatment. An early-phase clinical trial might be the first time an experimental cancer drug or intervention is used with people.

Phase II clinical trials

The goals of a phase II cancer clinical trial are to evaluate the effectiveness of the cancer treatment and to monitor side effects. While side effects are monitored in all phases of clinical trials, they are a special focus in phase II.

Phase III clinical trials

The goal of a phase III cancer clinical trial is to compare the new treatment to the standard treatment.

Phase IV clinical trials

The goal of a phase IV cancer clinical trial is to further assess the long-term safety and effectiveness of a treatment. A phase IV clinical trial is conducted after Food and Drug Administration approval.

Contact Mayo Clinic

For more information about participating in cancer clinical trials at Mayo Clinic, contact:

  • Mayo Clinic Comprehensive Cancer Center
  • Clinical Trials Referral Office
  • 855-776-0015 (toll-free)