Overview

• Phase 3 BWEL randomized nearly 3,180 women with stage II/III HER2-negative disease to a phone-based weight-loss program plus education versus education alone across more than 600 sites in the U.S. and Canada.
• At 12 months, the intervention group lost a mean 4.3 kg (4.7% of baseline) while controls gained 0.9 kg, with 46.5% achieving at least 5% loss and 22.5% reaching 10%.
• Participants completed a median 26 of 30 planned coaching calls in year one, and greater call completion correlated with more weight loss.
• Effects were smaller in premenopausal, Black, and Hispanic participants, who also completed fewer coaching calls than other groups.
• Investigators noted over 20% missing one-year weight measurements due to pandemic-related factors and limited full-cohort behavioral data, and the trial remains in follow-up to assess recurrence and survival.