Remote intervention helps women with breast cancer, obesity lose nearly 5% of body weight

Key takeaways:

• Remote intervention induced significant weight loss for women with breast cancer and obesity.
• Weight loss was observed across subgroups defined by patient and treatment factors.

A telephone-based weight-loss intervention helped women with breast cancer and obesity lose almost 5% of their baseline body weight, according to results of a randomized phase 3 trial.

Participants lost significant weight regardless of race, ethnicity, menopause status, income and more.

The data are the first from the Breast Cancer Weight Loss (BWEL) trial, which is evaluating whether weight loss can reduce recurrence, development of new cancers and mortality.

“This study really shows that weight loss is possible for patients with breast cancer,” Jennifer A. Ligibel, MD, professor at Harvard Medical School and senior physician in the Breast Oncology Center at Dana-Farber Cancer Institute, told Healio. “A structured weight-loss program can be very effective in younger and older patients, and in patients that have received a lot of different types of treatment.

“It’s not so simple for people to lose weight,” she added. “What we’re really hoping long-term from this program is to produce evidence that leads to insurance support for weight loss programs for patients with breast cancer and obesity, so that all patients who need them will have access to these programs..”

Will remote intervention work?

“Hundreds” of studies have evaluated the relationship between BMI and breast cancer incidence, recurrence and mortality, Ligibel said.

Healio reported on a meta-analysis by the Early Breast Cancer Trialists’ Collaborative Group presented at San Antonio Breast Cancer Symposium in 2024 that showed women with early-stage disease and a BMI of 25 kg/m² or higher had an increased risk for distant recurrence and death. Researchers observed the association regardless of a patient’s tumor characteristics, ER status or menopausal stage.

Women with breast cancer and obesity also have higher risk for lymphedema, surgical and radiation therapy complications, neuropathy, cardiovascular toxic effects, fatigue and comorbidities, according to study background.

Multiple studies have shown benefits of weight-loss programs for this patient population, but they have had small sample sizes, lacked diversity and focused on in-person interventions.

Ligibel and colleagues developed the BWEL trial to determine if a remote intervention could aid patients, too.

“The study is still ongoing, but in order to get to that primary outcome [recurrence, mortality and development of new cancers], there are a lot of other things that we’ll learn along the way, and one of the most important is, did this program actually help women lose weight?” Ligibel said. “You can’t test the impact of weight loss on cancer recurrence if people didn’t actually lose weight.”

The BWEL trial consisted of 3,180 women (mean age, 53.4 years; standard deviation, 10.6; 80.3% white) with stage 2 or 3 ERBB2-negative breast cancer and a BMI of 27 kg/m2 or higher.

Patients randomly assigned to the intervention (n = 1,591) received a 2-year, telephone-based intervention that emphasized weight loss through consumption of fewer calories and increased physical activity. They spoke individually with coaches at a call center at Dana-Farber.

These participants also received an activity monitor from Fitbit and meal replacement shakes from Nestle Health Sciences, but they were not required to use them.

The control arm (n = 1,589) received health education alone.

Both cohorts had the same mean weight at baseline (91.6 kg).

Weight change at 1 year served as the primary endpoint of this secondary analysis.

‘Significant weight loss’

Women in the intervention arm lost a mean 4.3 kg (95% CI, 3.9-4.6) or 4.7% of (95% CI, 4.3%-5%) of their baseline weight at 1 year. Conversely, those in the control arm gained a mean 0.9 kg (95% CI, 0.5-1.3) or 1% (95% CI, 0.1%-1.4%).

The intervention arm had a significantly higher percentage of patients who lost at least 5% (46.5% vs. 14.3%; P < .001) or 10% (22.5% vs. 5%; P < .001) of their body weight.

“This is what we had hoped for,” Ligibel said.

The intervention significantly reduced weight across subgroups of participants defined by menopausal status, race and ethnicity, BMI category, income, education, ER/PR status, smoking status, and previous chemotherapy or endocrine therapy.

However, some groups did have lower weight loss, including premenopausal women and those who identified as Black or Hispanic or Latino.

“We saw there was less weight loss in those groups, but there was still significant weight loss across all the different categories we looked at,” Ligibel said. “One of the other things we were really interested in was looking at women taking anti-estrogen therapy, because I know from taking care of women with breast cancer, people talk about how hard it is to lose weight when you’re taking anti-estrogen treatments, things like tamoxifen and aromatase inhibitors. We were really interested in looking at that, and we found that people were successfully able to lose weight even when they were on these medicines.”

Researchers acknowledged study limitations, including not having 1-year data from more than 20% of participants, partly due to the COVID-19 pandemic.

‘Poised to learn a lot’

Ligibel expressed hope that researchers would have enough data to evaluate their primary outcomes within “the next year or 2.”

“The great thing about breast cancer is that we continue to improve the outcomes of our patients, and so it takes a long time before you get enough of those cancer events to be able to look at your primary outcome.”

They do have other data to evaluate, though.

Researchers plan to present findings later this year on how participants used tools such as Fitbits and replacement shakes, and their impact on weight loss.

They also are evaluating weight loss trajectories to determine what worked and which patients had the best outcomes.

Ligibel and colleagues have data on how weight loss impacted metabolism, inflammation and insulin resistance, too.

“We hope to learn a lot more about the biologic connections between obesity and breast cancer to understand how weight loss could lower the risk of cancer recurrence.?” Ligibel said. “We are really poised to learn a lot about that from this study, given how many women were in the study and this robust weight loss.”

A quality-of-life analysis is coming, as well.

“One question that I always get asked is, what does this mean in the era of GLP-1 receptor agonists?” Ligibel said. “I think this study really does show that you can lose weight through a lifestyle-based approach, and I am hopeful that over the next years, we’re also able to show the many other benefits of making healthy lifestyle changes of exercising more and eating a healthier diet.”

If data continue to be positive, Ligibel envisions a future in which the intervention could be used across the country.

“We had about 10 coaches who worked with 3,000 patients,” she said. “If you think about the cost of many things we do in cancer care, you could set up a whole call center and treat thousands of patients for the cost of 1 year of immunotherapy for one patient.

“That’s the reason we developed this, to be delivered through the phone. To not require in-person visits. Initially it’s a weekly call, but then pretty quickly goes to every other week, and then monthly. One coach was working with hundreds of patients. That is a very cost-effective strategy.”

For more information:

Jennifer A. Ligibel, MD, can be reached at jennifer_ligibel@dfci.harvard.edu.