Two trials reported changes to the primary endpoint based on interim analysis [ 9, 15], one introduced an additional (secondary) endpoint [ 22] and one dropped an endpoint [ 23] subsequent to interim analyses.
No treatment change was made based on interim PET scan results.
An interview guide was used and was adjusted during the process of interviewing based on interim reviewing of the results.
One potential early prognostic marker that this study investigated is metabolic response based on interim and posttreatment FDG-PET.
Recommendations made by the DMC or based on interim analysis were identified and potential sources of bias assessed.
This is in contrast to adaptive designs that can alter the sample size based on interim results.
Response adaptive trial design could decrease the risk of increased mortality only after a large sample size has been evaluated (27) by adjusting randomization to the intervention or control as the RCT progresses based on ongoing interim analyses.
Other mechanisms are considered to be more problematic, such as all those based on unblinded interim analyses of efficacy.
From 1989, based on two interim analyses showing a significant improvement in recurrence-free survival among lymph node-positive patients, these node-positive patients were all allocated to the tamoxifen treatment arm (i.e., skipped the first randomization).
