ABSTRACT
Clinical trials are experiments conducted on human subjects for the purpose of evaluating one or more therapeutic interventions. Observational studies on cancer patients can generate knowledge about cancer behavior, biologic determinants of outcome, and hypotheses about therapeutic benefit. However, observational studies cannot control for factors that might influence outcome. Only through clinical trials can therapeutic interventions be reliably assessed. All aspects of the study rationale, objectives, design, treatments, data requirements, statistical justification, and analysis plan are detailed in the protocol document. As a clinical trial is an experiment, it must begin with a hypothesis or question: What are the toxic and/or biologic effects of a treatment or intervention? What effect does an intervention have on rates of tumor response, or on time to relapse, progression or death? To be successful, a study must clearly define the primary question and outcome measure(s) of interest, utilize an appropriate design and sample size to address the question, and collect and analyze data according to prespecified criteria. Increasingly clinical studies are enriched by the addition of secondary end points including quality of life and biomarker studies. Furthermore, studies conducted on human subjects must comply with international standards of ethical review and conduct. Finally, at the conclusion of each trial the interpretation of its results should be undertaken in the context of preexisting knowledge in the particular clinical setting studied. This chapter addresses all such aspects of clinical trials in cancer patients.
