Telephone coaching leads to weight loss for people with breast cancer | ASCO 2023

Background

Obesity is a risk factor for developing breast cancer. Among women who have had breast cancer, obesity increases both risk of recurrence and risk of death from breast cancer or any cause. One study found a 10 percent increase in the risk of breast cancer mortality and a 14 percent increase in the risk of second cancers for each additional 5 kilograms, or 11 pounds, of body mass index. Heart disease, which is linked to obesity, is the leading cause of death among women who have had breast cancer.

The Breast Cancer Weight Loss (BWEL) study tests a telephone-based coaching program to help women with breast cancer lose weight. The primary goal of the trial is to look at the impact of BWEL on overall survival. These early results focus on weight change, a secondary goal.

Results

After one year, BWEL telephone coaching resulted in an average weight loss of 4.4 kilograms or 9.7 pounds (4.8 percent of body weight). People who did not receive telephone coaching gained an average of 0.7 kilograms or 1.5 pounds.

The phase III randomized BWEL trial initially enrolled 3,180 participants from 600 sites. The study coincided with the COVID-19 pandemic, resulting in above-average withdrawal from the program. The final study group includes 2,395 participants. All were diagnosed with stage II or III HER2-negative breast cancer within a year of joining the study. The group consists of people with both hormone receptor-positive and hormone receptor-negative breast cancers.

At the start of the trial, participants had completed surgery, chemotherapy, and in some cases radiation therapy. Their average age was 53.4 years. More than half were postmenopausal at the time of their diagnosis with breast cancer. This study used body mass index (BMI) to identify participants. BMI is a controversial but widely used weight measure. A healthy BMI is between 18.5 and 24.9. Study participants had an average BMI of 34.5.

The 2-year study randomly assigned participants to the coaching group or the control group. People in both groups received standardized health education materials, greeting cards, and a subscription to a health-related magazine of their choice. Half the participants, chosen randomly, also received regular weight-loss coaching by phone for a total of 42 calls over 2 years.

Coaching focused on both diet and physical activity. Each participant had a 10 percent weight-loss goal, as well as goals for calorie intake and physical activity. They aimed to exercise 150 minutes per week in the first 6 months of the program. In months 7 to 24 — the weight-loss maintenance phase of the program — this goal increased to 220 minutes per week.

While all participants in the telephone coaching group lost weight, certain subgroups lost less weight. Specifically, the program was not as effective for Black, Hispanic, and premenopausal women.

What does this mean for you?

If you are trying to lose weight, ask your healthcare team if they offer BWEL or another telephone-based coaching program. BWEL’s telephone coaching was based on a standard telephone coaching approach and may be available under a different name at your hospital or clinic.

While exciting, the results of this study also point to areas for future research and the need for more tailored programs for Black, Hispanic, and younger women. These groups all lost weight, but not as much as postmenopausal white women.

If you look for weight-loss programs, ask how they measure weight. This study used body mass index to measure weight. Future studies by this group will use body composition. Many healthcare professionals and equity advocates have criticized body mass index as discriminatory because the standard does not take into account racial and ethnic differences in body type and weight. Body composition measures fat mass and is less likely to classify people with significant muscle mass as overweight.