Clinical Trials

Clinical Trials: A Practical Guide ■❚❙❘Table 1. Survival data for 36 patients with pancreatic cancer in a trial of a new treatment versus thestandard treatment.New treatmentStandard treatmentSurvival time Survival status Survival time Survival status(months) (0 = survival, 1 = dead) (months) (0 = survival, 1 = dead)2 0 3 05 0 5 110 1 6 012 1 7 115 0 8 127 1 10 136 0 11 036 0 12 137 1 13 038 0 15 139 0 16 041 0 23 142 0 30 144 0 39 145 1 40 146 0 45 148 0 48 048 0 48 0Table 2. Reasons for censoring observations in clinical trials.ReasonLost to follow-upPatient withdrawnPatient has an outcome that prevents the possibilityof the primary endpoint (competing risk)Study terminationExamplePatient moved away or did not wish tocontinue participationPatient withdraws from the study due to side-effectsDeath from cancer where death from cardiac causesis the primary endpointAll patients who have not died are consideredcensored at the end of the study237