Jennifer A. Ligibel, MD, on Weight Loss and Early-Stage Breast Cancer: Impact of Telephone-Based Intervention

Jennifer A. Ligibel:

Obesity at the time of breast cancer diagnosis is a poor prognostic factor. We know that women with obesity, when they're diagnosed with breast cancer, have a higher risk of cancer recurrence, cancer related mortality, and all cause mortality compared to women with a BMI in the normal range at diagnosis. What we don't know is whether losing weight after being diagnosed with breast cancer will improve outcomes. The breast cancer weight loss trial is a phase three randomized trial that will test the impact of a telephone-based weight loss program on invasive disease-free survival in women with stage two and three breast cancer who have a body mass index of at least 27 at the time of study entry. The breast cancer weight loss trial enrolled 3180 women from across the United States and Canada. Women came from 600 different sites, and they were enrolled over about four and a half years.

Average age of participants in the study was 53. The average body mass index was 34.5. In the obese range. About 20% of women had triple negative breast cancers, and 80% had hormone receptor positive, HER2 negative breast cancers. Most of the patients received chemotherapy. 90% of the patients with hormone receptor positive cancers received endocrine therapy. And almost 90% of patients were treated with radiation. About 13% of the patients were African-American, and seven and a half percent of the women were Hispanic with the rest being non-Hispanic white. A lot of women with breast cancer will gain weight. And weight is a major topic of discussion for breast cancer survivors. This study really sought to enroll women and determine whether a lifestyle based weight loss program would improve outcomes. Our intervention was delivered by phone. Each patient was matched with a health coach at a call center at Dana Farber.

Patients received 42 telephone calls over two years. Calls initially were weekly and then biweekly, and then finally monthly in the last year of study participation. The program focused on caloric restriction and increased physical activity. Women were enrolled in the study after they had completed their standard breast cancer surgery, radiation, and chemotherapy if delivered. The weight loss program was a two-year program for patients who were enrolled. They worked closely with their coach through that period of time, especially in the first six months, which was the really intensive part of the weight loss program. The study went on through the COVID pandemic, and so keeping patients connected to the study was something that we worked very hard to do. We had webinars that keep patients updated, the study, status, information about diet and exercise. We had a newsletter. We sent patients mailings about healthy living.

We really tried, in a lot of different ways, through the telephone and the web to keep people connected to the study. We did find that the intervention was successful in reducing weight in the population as a whole. We found a 5.6% weight loss in women who are randomized to the weight loss program versus patients who were enrolled to the control group. But, we found that there was some differences in the weight loss that patients experienced, depending on their age, their race. We found that younger women lost a bit less weight than older women, if they were enrolled in the weight loss program. We found that African-American women lost less weight than white women. We found that African-American women enrolled to the control population actually gained more weight than other groups of patients enrolled to the control population. We will be looking at these data over time to really think about whether there may be additional tools, resources that we could offer to some of the patients that didn't experience as much weight loss with the intervention.

But again, we were really happy to see that the intervention was successful across all groups, such as the absolute weight loss differed a little bit by some of these characteristics. We found that women who were randomized to the weight loss intervention group lost 5.6% of their baseline body weight compared to women randomized to control. It was about a 12 pound weight differential between the two groups, which was highly statistically significant. We also found significant weight loss across all of the patient subgroups that we looked at by age, by race, ethnicity, economic status, education level, hormone receptor status of the tumor. We were very happy to see that the weight loss program seemed to be successful across the study.