Do investigators show selection biases when enrolling patients in phase I oncology registration trials?

ObjectivesThe goals of this study are: (1) to provide a descriptive analysis of the characteristics of patients enrolled in phase I oncology registration trials in Japan and the United States of America (USA) and (2) to evaluate whether the trial populations were representative of the total cancer populations in these two countries.Materials and methodsWe examined the median age, gender distribution, and performance status of patients enrolled in 133 phase I oncology registration trials of 33 drugs. Data were included from trials in Japan and the USA. We also estimated the median age and gender proportion of the total cancer population in Japan and the USA.ResultsThe estimated median age of patients enrolled into phase I oncology registration trials was 58 years, which was lower than the median age of patients in the Japanese and the USA cancer populations (70 and 66 years, respectively). Of the patients enrolled in registration trials, approximately 60% were male; this is higher than the proportion of males in the total cancer populations in both Japan and the USA (43% and 52%, respectively). The proportion of enrolled patients with a performance status of 0–1 was approximately 90%, in both Japanese and the USA cancer populations.ConclusionInvestigators enroll a lower proportion of older cancer patients on phase I oncology registration trials.