Randomised consent designs in cancer clinical trials

Pragmatic Trials

“…In the double consent variant, consent to treatment is sought from both groups and those who decline the allocated treatment receive the other. 133 This method has practical advantages in screening and other trials where blinding in the experimental group is impractical, but awareness of allocation among controls might lead to contamination, or where the process of recruitment and consent would constitute a partial intervention -for example, in a trial of sending postcards to patients to prevent readmission to hospital for deliberate self harm, where writing to seek consent from patients in the control group would mimic the intervention. 134 Randomised consent may also be ethically preferable to a conventional design in studies where it would be intolerable for those in the control group to know that a potentially life-saving treatment was being denied through randomisation.…”

The WHO Antenatal Care Randomised Controlled Trial: rationale and study design

“…34 Although these authors discouraged it for cancer therapeutic trials, where individuals are the unit of randomisation, we believe that most of the limitations identified by them either do not apply or are unavoidable because of the characteristics of community trials, especially where different geographical units are randomised. This concept seems to be shared by experts in the field (D. Altman, personal communication to J. Villar;Oxford, UK, 1996).…”

Current statistical issues in clinical cancer research

“…Some examples of the influence of cancer research on statistical methodology were given earlier. Another is the randomised consent design for controlled trials proposed by Zelen (1979), although this controversial design has rarely been used in cancer trials (Altman et al, 1993). A more recent example is the methodology being developed to design and analyse studies of quality of life, which is the subject of another of the forthcoming editorials.…”