Rates of and factors associated with patient withdrawal of consent in cancer clinical trials

Patient withdrawal of consent from a cancer clinical trial can undermine the trial’s purpose, make the original sample size and power calculations irrelevant, introduce bias between trial arms, and prolong the time to trial completion. A cohort study of 11,993 patients from 58 trials found small but consistent rates of withdrawal among patients who were Hispanic, older, enrolled in a placebo-controlled trial, or not receiving radiation. The authors conclude that these factors should be considered when designing future cancer clinical trials.