Most young women diagnosed with breast cancer are not physically active in the months after a cancer diagnosis, but physical activity increased over time. According to data presented at the 2016 Cancer Survivorship Symposium, higher levels of physical activity were seen among women whose oncology providers addressed the issue, suggesting the importance of enhancing patient and provider engagement with healthy lifestyle information and recommendations.¹

“In this large cohort of breast cancer survivors, more than 50% engaged in no physical activity at all in the initial months after cancer diagnosis, but physical activity increased over time,” said Jennifer A. Ligibel, MD, Director of the Leonard P. Zakim Center for Integrated Therapies at the Dana-Farber Cancer Institute and Assistant Professor of Medicine at Harvard Medical School, Boston.

“Despite increases in physical activity, however, body mass index rose slightly over the study period, with women who received chemotherapy more likely to gain weight,” she added.

Lifestyle Factors Linked to Survivorship

As Dr. Ligibel reported, growing evidence suggests that physical activity and weight may be linked not only to how people feel after they’ve been diagnosed with breast cancer, but to rates of cancer recurrence and overall survival.

A meta-analysis of 82 individual studies looking at the relationship between a woman’s weight at the time of cancer diagnosis and her risk of dying of breast cancer or other causes found that women who were obese when diagnosed with breast cancer had a 35% higher risk of dying of breast cancer and a 41% higher risk of dying of any cause in the years after their diagnosis.²

Additional studies have shown that weight and activity may be especially important in young women, said Dr. ­Ligibel, but few trials have tested physical activity interventions in this cohort.

Young and Strong Study

A cluster-randomized study evaluating the effect of educational interventions for 467 young breast cancer survivors, the Young and Strong study randomized sites 1:1 to a young women’s intervention focusing on fertility and other issues facing young women or to a physical activity intervention.

The majority of the patients had undergone fairly extensive surgery. Almost 40% had had bilateral mastectomy, 40% had undergone lumpectomy, and 80% had received chemotherapy. In addition, approximately half of patients had received radiation, and the majority received endocrine therapy, largely in the form of tamoxifen.

At physical activity intervention sites, providers were instructed to discuss physical activity with patients, and participants were given materials to encourage exercise. Physical activity was measured at baseline and at 3, 6, and 12 months.

At baseline, women engaged in 80 minutes of moderate to vigorous physical activity per week. By 12 months, this increased significantly to an average of 130 minutes of activity. Dr. Ligibel and colleagues also observed an increase in the proportion of patients who reported any activity.

“At baseline, fewer than 50% of patients reported that they engaged in any type of recreational activity,” said Dr. Ligibel, “but this had increased to about 65% of patients by 12 months.”

Finally, researchers looked for predictors of change in physical activity and found no relationship with any of the treatment variables. “We also found no correlation between change in activity and patient factors like age, race, ethnicity, or income,” Dr. Ligibel reported.

Weight Gain and Chemotherapy

Over the 12-month follow-up period of this study, researchers found a statistically significant, albeit small, increase in weight, with average body mass index increasing from 25.4 kg/m² to 25.8 kg/m². This equated to an average 3-pound weight gain.

“We looked for factors of weight change and found that the most significant factor of weight change was the receipt of chemotherapy,” Dr. Ligibel reported. “Women who received chemotherapy had an average weight gain of 4 pounds, with a standard deviation of 16 pounds…. Some patients gained quite a lot of weight in this cohort.” On the other hand, women who did not receive chemotherapy gained no weight on average.

“There was no statistical significance between any of our other treatment factors and weight gain in this trial. There was also no correlation between changes in physical activity and a change in body mass index,” Dr. Ligibel observed.

Future Directions: The BWEL Study

Opening this spring, the Breast Cancer Weight Loss (BWEL) study will test whether losing weight after being diagnosed with breast cancer lowers the risk of recurrence. The study will enroll 3,136 women throughout the United States and Canada who have a body mass index of at least 27 kg/m² and have stage 2 or 3 breast cancer. Participants will be randomized to a 2-year telephone-based weight loss intervention or a health education alone arm.

“With this trial,” Dr. Ligibel concluded, “we will be able to say something more definitive about the role of weight loss in young breast cancer patients.” ■

Disclosure: Dr. Ligibel reported no potential conflicts of interest.

References

1. Ligibel JA, Barry WT, Ruddy KJ, et al: Physical activity and weight patterns in a study cohort of young breast cancer survivors. 2016 Cancer Survivorship Symposium. Abstract 166. Presented January 16, 2016.

2. Chan DS, Vieira AR, Aune D, et al: Body mass index and survival in women with breast cancer: Systematic literature review and meta-analysis of 82 follow-up studies. Ann Oncol 25:1901-1914, 2014.