Prevention of Breast Cancer Recurrence Through Weight Control, Diet, and Physical Activity Intervention

BACKGROUND/MAIN OBJECTIVE: The main purpose of our study is to assess the effect of a lifestyle intervention combining weight control, diet and physical activity on the risk of recurrences among breast cancer patients with non-metastatic tumours. As secondary objectives we aim to assess whether the proposed intervention is able to improve the overall survival or the disease-free survival, as well as quality of life of breast cancer patients. METHODOLOGY: This multicentric randomized controlled trial aims to include 2108 women (1054 per arm), aged up to 75 years, diagnosed with a non-metastatic breast cancer (stage I, II, IIIA) in the participating centres, whose standard treatment was completed within the last 3 months. Participants will be assigned to either an intervention or a control group, and followed for five years. Patients assigned to the control arm will continue with the usual care, including standard guidelines for weight control applied in the centre. Patients in the intervention group will be involved in a lifestyle program with two components. The dietary part will aim to achieve a calorie reduction while maintaining nutritional quality; the physical activity part will include supervised sessions of moderate intensity. Data will be analyzed on an intention to treat basis using time-toevent analysis. HYPOTHESES: We expect a significant reduction in the 5-year cumulative incidence of recurrences (primary outcome) in the intervention group. Furthermore, as secondary outcomes, we expect a significant increase in overall survival and an improvement of quality of life of patients included in the intervention arm.