Authors’ reply to SohBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2682 (Published 09 April 2014) Cite this as: BMJ 2014;348:g2682
- Robert J C Steele, professor of surgery1,
- Annie S Anderson, professor of public health nutrition1
- On behalf of the BeWEL team
- 1Centre for Research into Cancer Prevention and Screening, Cancer Division, Medical Research Institute, Ninewells Medical School, Dundee DD1 9SY, UK
As Soh correctly points out,1 2 a fully powered study would take a very long time to show any effect on cancer reduction given the long latent period between adenoma formation and the development of invasive cancer. However, a study powered to show a reduction in the recurrence of adenoma would require colonoscopy in both the study and control groups, and it would be unethical to leave adenomas in situ, so it would be impossible to carry out such a study with cancer occurrence as an endpoint. We do, however, believe that it would be valuable to carry out a study with adenoma recurrence as an endpoint because an effect would add considerable weight to the argument for weight reduction and physical activity as a way to reduce cancer risk using adenoma recurrence as a surrogate. As far as crossover is concerned, we would agree that the control group should be offered the intervention if it is shown to be beneficial, but this would not affect the validity of the results for the reasons given above.
Cite this as: BMJ 2014;348:g2682
Competing interests: None declared.