Conducting chemoprevention clinical trials: challenges and solutions.

The clinical trials investigative team faces a number of challenges during the execution of a chemoprevention protocol that often depend on the phase of the trial. Phase II chemoprevention trials test promising agents for biomarker modulation in cohorts of 30 to 200 participants at greater than average risk of the cancer being studied who meet strict eligibility criteria. By contrast, phase III trials test agents for their efficacy in cancer prevention in thousands of participants who are generally healthy or may be at slightly elevated risk. Consideration must be given to accruing a very large cohort or a smaller but relatively rare group of participants, and to maintaining vigilance over the toxicity profile of the agent, which may be taken for a lengthy period of time. Additional considerations include clear communication to the participants of the risks and benefits associated with participating on the trial, as well as the need for their long-term commitment. In light of the layer of complexities that chemoprevention research adds to clinical trials, one or more team members need a unique set of skills and knowledge, beyond understanding the scientific aspects of the trial. Published by Elsevier Inc.