Informed consent to cancer clinical trials

Li Liu, MD

University of Pennsylvania Cancer
Last Modified: May 12, 2001

Presenter: S. Joffe
Affiliation: Dana-Farber Cancer Institute, Boston, MA


    For valid informed consent to be obtained, the prospective subject must have an understanding of the medical and research issues involved to make an informed and enlightened decision. Assuring an understanding of the research procedure requires thorough and repeated discussions with the subject on an ongoing basis, both before and after the documentation of consent.

Materials and Methods:

  • Quality of Informed Consents (QuIC) to 287 adult cancer patients who perticipated in clinical trials
  • Each patients healtcare provider was also surveyed


  • 72% patients responded
  • Improved knowledge was associated with college education, English speaking only, not signing the consent form at the initial discussion, the presence of a nurse, and careful reading of the consent form
  • Majority of respondents were satisfied with the informed consent
  • Only about half of the patients understood why clinical trials are performed

Authors' Conclusions

  • Misunderstanding of the informed consent was quite common in patients who were enrolled in clinical trial
  • Health providers may share the same misconceptions

Clinical/Scientific Implications:

  • In the setting of oncology clinical trials, educating patients to understand the underlying goals of cancer clinical trials may be difficult to accomplish. Oncology therapeutic protocols often involve multiple modalities, such as standard and high-dose chemotherapy, radiotherapy, surgery, and immunotherapy, which can be administered over a prolonged time period
  • There may be one or more randomizations between substantially similar therapies, or radically different therapies
  • These combinations of multiple therapies can make the consent process confusing

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