For people with breast cancer who have a body weight that is classified as overweight or obese, participating in a telephone-based weight loss programmeme can help improve their physical function and overall quality of life.

The research will be presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place May 29 to June 2 in Chicago. 

Previous results from the phase 3 Breast Cancer Weight Loss (BWEL) clinical trial found that a telephone-based weight loss programme could help people with breast cancer who had a body mass index (BMI) classified as overweight or obese experience meaningful weight loss.

The BWEL weight loss programme helps participants reduce their caloric intake and increase their physical activity by using behavioural strategies to help them reach diet, exercise, and overall weight loss goals.

Over the course of the 2-year programme, participants were assigned a coach they would speak with on the phone up to 42 times.

In this substudy of the BWEL clinical trial, the researchers wanted to learn whether the weight loss programme could also help improve physical function and quality of life for participants.

The participants were randomly assigned to either take part in the weight loss programme and receive health education (272 participants) or to receive only health education (270 participants).

Health education included a variety of learning materials about the importance of following a healthy diet and getting regular physical activity. 

Researchers evaluated participants’ physical, mental, and social health by asking questions from the Patient-Reported Outcomes Measurement Information System (PROMIS).

PROMIS uses a scale where 50 equals the average in the U.S. general population.

Scores were collected at the time of enrolment, then 6 months and 2 years later.

Key findings

The study found that at 6 months, the participants in the weight loss programme group had meaningful improvements in their quality of life compared to those in the health education group.

The participants in the weight loss programme group had better physical function, with an average difference in score that was 1.9 points higher than those in the health education group.

They also had better overall physical health (2-point average difference in score) and better overall mental health (1.3-point average difference in score). 

Those who participated in the weight loss programme also had improvements in their social roles and activities, like their ability to work and socialise, with an average score difference of 2.3.

They had reduced fatigue as well, with an average score difference of 1.7 points lower than participants in the health education group.

The researchers found that each of these improvements were generally maintained 2 years after enrolment.

“The BWEL programme was delivered to more than 1,500 participants enroled from across 635 oncology practices in the U.S. and Canada. These findings thus show not only that weight loss provides meaningful benefits for people who have both breast cancer and obesity, but also that this can be achieved in thousands of patients enroled across many kinds of oncology practices,” said lead author Jennifer Ligibel, MD, Director of the Leonard P. Zakim Center for Integrative Therapies and Healthy Living at the Dana-Farber Cancer Institute. 

“We've asked patients with stage II to III breast cancer who are overweight or obese to lose weight for years without offering them much of a structured programme. BWEL changes that conversation not just because of the survival data, but also because patients in the intervention arm felt measurably better in their physical function, fatigue, and social engagement. A programme that improves survival and quality of life simultaneously is a programme worth delivering,” said Marcin Chwistek MD, FAAHPM, Chief of Supportive Oncology and Palliative Care programme at Fox Chase Cancer Center and an ASCO Expert in supportive care.

The researchers plan to evaluate whether baseline physical functioning and quality of life are associated with the success of the weight loss intervention.

To help determine who could benefit most from this intervention, they hope to learn whether participants’ baseline physical functioning and quality of life predicted how successful the intervention was.

The researchers are also interested in studying whether weight loss predicts improvements in patient-reported outcomes.

This will provide insight into whether weight loss itself, rather than participating in the coaching calls, is most closely linked to the improvements seen in physical function and quality of life.

This study was funded by the National Cancer Institute, the Susan G. Komen Foundation, the Breast Cancer Research Foundation, and the American Cancer Society.

Source: ASCO