Early stopping rules in oncology: considerations for clinicians.

The number of cancer-related clinical trials has been rapidly increasing over the past decade. Along with this increase, oncology studies stopped early for benefit or harm have also been more common. Clinicians treating cancer patients often are faced with the challenge of having to decide whether or not to incorporate information from these new studies into their daily clinical practice. This review article explains the role of the Data and Safety Monitoring Committee in stopping trials early; provides examples of oncology trials stopped early; and reviews some of the controversies and statistical concepts associated with early stopping rules. In addition, a simple and practical approach to interpreting the findings of trials that are stopped early is provided to assist clinicians in deciding how to incorporate information from these studies into their daily practice.