ASCO Perspective 

“We know that being overweight increases one’s risk for breast cancer and breast cancer recurrence, but we don’t yet know whether weight loss can reverse the effects and improve outcomes. Weight loss in any capacity is challenging to obtain and sustain. This study demonstrates that consistent health coaching by telephone – a more accessible, cost-effective approach compared to in-person programs – can significantly help patients with breast cancer lose weight over one year and is effective across diverse groups of patients. We anxiously await longer-term follow up to see whether this weight reduction will ultimately improve outcomes for these patients,” said Elizabeth Anne Comen, MD, ASCO Expert. 

*Release includes additional data not in the abstract. 

ALEXANDRIA, Va. — Patients with breast cancer in the overweight or obese body mass index (BMI) ranges can achieve meaningful weight loss through a telephone-based intervention. The research will be presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting.  

Study at a Glance 

Key Findings 

The telephone-based coaching intervention used in the Breast Cancer Weight Loss (BWEL) trial successfully led to a reduction in weight in the almost 1,600 participants randomized to the weight loss intervention group, across different age groups, races, and ethnicities, demonstrating that weight loss can be achieved in a diverse population of patients with breast cancer. 

Across all subgroups, patients in the intervention arm lost significantly more weight than patients in the control arm, losing an average of 4.8% of body weight at 12 months (non-Black, non-Hispanic: 5.4%; Hispanic: 3.2%; Black: 1.6%.). In the control group, patients gained an average of 0.9% of body weight (non-Black/non-Hispanic: 0.7%; Hispanic: 1.0%; Black: 2.1%). The intervention led to significant weight loss vs controls in all patient groups, however, the amount of weight loss varied by menopausal status (postmenopausal patients in the weight loss group lost more weight than premenopausal women in the weight loss group) and race/ethnicity, not hormone receptor status. 

"Our study provides compelling evidence that weight loss interventions can successfully reduce weight in a diverse population of patients with breast cancer. The next step will be to determine whether this weight loss translates into lower rates of cancer recurrence and mortality. If our trial is successful in improving cancer outcomes, it will have far-reaching implications, demonstrating that weight loss should be incorporated into the standard of care for survivors of breast cancer,” said lead author Jennifer A. Ligibel, MD, FASCO, Associate Professor of Medicine at the Dana-Farber Cancer Institute. 

About the Study 

This trial is the first phase III study designed specifically to assess whether a structured weight loss program could reduce cancer recurrence and mortality in patients in the overweight or obese BMI ranges with stage II-III breast cancer. More than 3,181 patients enrolled in the trial, from more than 600 sites in the U.S. and Canada between August 2016 and February 2021. Patients eligible for the study had completed chemotherapy and radiation therapy (if given) and were within 14 months of diagnosis of stage 2-3 HER2-negative breast cancer. The average BMI of participants was 34.5 kg/m2, and mean age was 53.4 years.  

At the time of diagnosis, 57% of patients were postmenopausal, 80.3% White, 12.8% were Black, and 7.3% were Hispanic. The trial randomly assigned participants to an intervention group (telephone-based weight loss intervention plus health education) or a control group (health education alone). Changes in weight were measured by height and weight measurements at baseline and 12 months and compared between groups.  

Next Steps 

Next, researchers will assess whether the weight loss intervention impacts cancer recurrence and mortality, the primary outcome of the trial. The study is also examining exercise levels and dietary changes of participants to better understand the effect of the weight loss intervention on overall health. Researchers also plan to analyze changes in serum biomarkers related to metabolic, inflammatory, and immune pathways to uncover the mechanism by which obesity impacts breast cancer. 

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