Trial Information

The Effects of Equivalent Weight Loss With or Without Exercise Training on Breast Cancer Risk Biomarkers in Postmenopausal Women: the SHAPE-2 Study

Postmenopausal women who are sedentary or overweight, have an increased breast cancer risk.
It is suggested that these two factors mediate breast cancer risk mainly through sex
hormone-related pathways. However, an inactive lifestyle and obesity are highly correlated
and it is not clear which is most relevant to risk.

Literature shows that weight loss/ fat loss reduces postmenopausal sex hormone levels, but
the question is if there is an additional beneficial effect on hormones of reaching this
weight loss by physical activity instead of nutritional interventions.

In this three-armed, two-center intervention study, 250 sedentary postmenopausal women who
are aged 50-69 years will first enter a run-in period of 5 weeks. During this period, all
participants get a diet, adapted to the guidelines for healthy nutrition, meeting their
energy expenditures to maintain stable weight. After this run-in phase they are randomly
allocated to a (1) diet induced weight loss group, (2) a combined exercise and diet induced
weight loss group or (3) a control group. Participants allocated to the dietgroup will get a
calorie restricted diet of -500 kCal/day, they will remain their habitual exercise pattern.
Participants in the combined group will follow an exercise programme (combined endurance and
strength) of 4 hours of sports per week with an average energy expenditure of 350 kCal/day
and a, less strict. And a calorie restricted diet of -250 kCal/day. The aim of both
intervention groups is to loose 5-6 kg of body weight during the 14 week intervention
period. Participants in the control group are requested to retain the baseline diet and
their habitual exercise pattern. Primary study parameters measured at baseline and after 21
weeks are: serum concentrations of endogenous estrogens, endogenous androgens and sex
hormone binding globulin. Other study parameters include: body fat distribution, amount of
total and abdominal fat, weight, BMI, physical fitness, blood pressure and lifestyle
factors.

The aim of this study is to provide insight into the effect of weight loss mainly driven by
exercise compared to equivalent weight loss due to nutritional calorie restriction on breast
cancer biomarkers. Furthermore, we are specifically interested whether weight loss mainly
due to physical exercise induces greater amounts of fat loss (total and abdominal) and
subsequently results in more favourable effects on these hormones compared to equivalent
diet-induced weight loss.