JNCI April 28 tip sheet( Designing a Randomized Controlled T...),Health

Designing a Randomized Controlled Trial for Physical Activity, Weight Control, and Breast Cancer Risk

Researchers describe the rationale and a possible design for randomized controlled trials that test the impact of physical activity and weight control on breast cancer risk.

There are substantial observational data suggesting that regular physical activity and maintaining a healthy weight are associated with a reduction in breast cancer risk: however, it is unclear whether the apparent association is due to unknown confounding factors. An important way to determine if the lifestyle choices have a causal relationship with breast cancer risk is to test the hypothesis in the setting of a randomized controlled trial.

In the current commentary, Rachel Ballard-Barbash, M.D., of the National Cancer Institute in Bethesda, Md., and colleagues present designs for two trials, one in women who are at high risk of disease and one in breast cancer survivors. The interventions in the two trials could be the same; the goal for the weight control intervention would be a 10% weight loss for women with a body mass index above 25 kg/m2 at enrollment and avoidance of weight gain for those below 25 kg/m2. The goal for the physical activity intervention would be to achieve and maintain 150-220 minutes of physical activity per week.

"In conclusion, given the magnitude of the public health problem and the amount of accumulated evidence in support for this next level of scientific evidence, it is now appropriate to explore in detail the feasibility and timing of a large randomized trial to assess the effects of physical activity and weight control on breast cancer risk and/or prognosisand the trade-offs in moving toward the prevention vs the survival trial," the authors write.

Contact: NCI press office, ncipressofficers@mail.nih.gov, 301-496-6641

Clusterin A
'/>"/>