Remote Weight Loss Intervention Reduces Body Weight in Women With Breast Cancer

The Breast Cancer Weight Loss (BWEL; NCT02750826) is the first successful large-scale randomized clinical trial to demonstrate the ability of a phone-delivered weight loss intervention (WLI) in a diverse population of women with breast cancer.1

Participants randomly assigned to the intervention group saw greater weight loss, which researchers believe may set the stage for further research to evaluate the impact that a WLI might have on reducing the risk of recurrence and cancer-specific mortality. The study, published in JAMA Oncology, took a second look at the results of the BWEL trial, which included patient data from 3180 women who were diagnosed with stage II or stage III HER2-negative breast cancer, had a body mass index (BMI) of 27 or higher, and completed surgery, chemotherapy, or radiation therapy at least 21 days before enrollment in the trial.

A remote weight loss intervention in women with breast cancer has been shown to reduce body weight. | Image Credit: © Andrey Popov - stock.adobe.com

BWEL Trial Design

The phase 3 trial randomized participants into a WLI group and a control group. The WLI group received a 2-year telephone-based lifestyle intervention built on social cognitive theory and helped participants focus on building knowledge about their health and weight loss, self-monitoring, goal setting, problem solving, and stimulus control. The telephone interventions were partnered with health coaches based at a call center at the Dana-Farber Cancer Institute and conducted weekly for the first 12 weeks and then biweekly for the remainder of the trial.

This remote program was designed to promote weight loss through caloric restriction and increase physical activity, more specifically, an energy deficit of 500 to 1000 kcal/day to encourage weight loss of up to 1 to 2 pounds per week. The initial calorie range was based on participants' baseline body weight. Exercise goals were set at 150 minutes of moderate or vigorous recreational physical activity a week for the first 6 months and then 225 minutes a week between months 6 and 12.

All participants, both the WLI group and the control group, received a health education workbook and tools, including an activity monitor, meal replacement shakes, alternative dietary plans, and recipes tailored to the individual needs of each participant. The health education program they received also included quarterly study newsletters, bi-annual webinars, and mailings of educational materials.

Of the 3180 women in the BWEL trial, 1591 were randomized into the WLI group and 1589 into the control group. The average baseline characteristics held no difference between the groups. At baseline, the mean age was 53.4 years, and the mean BMI was 34.4. Out of all the participants, 406 (12.8%) were Black, 231 (7.3%) were Hispanic or Latino, 2906 (91.4%) were non-Hispanic, and 2555 (80.3%) were White. Furthermore, 2577 participants had received neoadjuvant or adjuvant chemotherapy, 2800 had undergone radiation therapy, and 2386 of 2530 participants with HR-positive cancers (94.3%) received endocrine therapy.

Differences in Weight Loss

In the WLI group, weights at 6 months and 1 year were available for 1366 participants (85.9%) and 1225 participants (77.0%), respectively. Similarly, weights in the control group at 6 months and 1 year were available from 1318 (82.9%) and 1176 (74.0%) participants, respectively. Study authors noted that 47% of the missing weights would have been collected during the first 18 months of the COVID-19 pandemic. Individuals with missing weight data were more likely to have HR-negative tumors, to be Black, and to have an annual household income of less than $50,000.

The mean weight at baseline in the WLI group and control group was relatively similar (91.6 kg). However, at 6 months, the mean weight in the WLI group was 87.2 kg, whereas in the control group it was 91.8 kg; and at 1 year, the mean weights were 87.3 kg and 92.5 kg, respectively. When adjusted for covariables (menopausal status, baseline BMI, HR status, race and ethnicity, education level, income level, and smoking status) using a linear mixed model, the WHLI group lost a mean of 4.3 kg (95% CI, 3.9-4.6 kg) of baseline body weight at 1 year, whereas there was a mean of 0.9 kg lost at 1 year in the control group.

“The WLI effect differed by menopausal status and by race and ethnicity, with less weight loss in premenopausal participants and in Black and Hispanic or Latino participants,” the study authors wrote. “But weight loss did not differ significantly by education level, socioeconomic factors, or treatment factors, including receipt of chemotherapy and hormonal therapy.”

The weight loss achieved in this study is similar to that seen in other lifestyle-based weight loss studies in women, even those with in-person and more intensive interventions. For example, the Exercise and Nutrition to Enhance Recovery and Good Health for You (ENERGY; NCT01112839) trial demonstrated that an in-person, group-based WLI (vs a less-intensive control intervention) led to a loss of 6.0% of baseline body weight at 1 year (vs a 1.5% loss in control group participants).2

“BWEL’s success in achieving similar weight loss as seen in these studies, across a large study population and through a remotely delivered WLI, demonstrates the feasibility of widespread implementation of weight loss as a treatment strategy in early breast cancer,” the current study’s authors suggested.1

The limitations of this study were not limited to the missing weight data of more than 20% of participants. The populations missing weight were more likely to be slightly younger, be Black, have HR-negative cancer, and report a lower level of household income. Additionally, detailed diet and exercise data were not obtained from all participants but only from those who were a part of a smaller, separate, preplanned substudy.

“The BWEL trial provides a path to reduce toxic effects, reduce the risk of comorbidities such as diabetes and cardiovascular disease, and improve quality of life in the growing population of patients with cancer and obesity,” the study authors concluded.

References

1. Ligibel JA, Ballman KV, McCall L, et al. Impact of a weight loss intervention on 1-year weight change in women with stage II/III breast cancer: secondary analysis of the Breast Cancer Weight Loss (BWEL) trial. JAMA Oncol. Published online August 21, 2025. doi:10.1001/jamaoncol.2025.2738

2. Rock CL, Flatt SW, Byers TE, et al. Results of the Exercise and Nutrition to Enhance Recovery and Good Health for You (ENERGY) trial: a behavioral weight loss intervention in overweight or obese breast cancer survivors. J Clin Oncol. 2015;33(28):3169-3176. doi:10.1200/JCO.2015.61.1095