Exercise may aid weight management for breast cancer survivors on endocrine therapy
New research from the University of British Columbia Okanagan (UBCO) offers promising insights into how exercise can support weight management for women who have survived breast cancer and are undergoing estrogen-blocking therapy. The study, led by Dr. Sarah Purcell of UBCO’s Southern Medical Program and Centre for Chronic Disease Prevention and Management, investigates a question that has puzzled clinicians for years: how does long-term endocrine therapy influence weight, and can exercise counteract these effects?
Breast cancer survivors generally enjoy favorable survival rates, but many face a heightened risk of weight gain during and after treatment. Excess weight is not just a cosmetic concern; it is linked to obesity-related health issues such as heart disease and diabetes and may also influence cancer recurrence. Identifying why this specific population gains weight and how to prevent it is a priority for researchers and clinicians alike.
Dr. Purcell explains that the mechanisms behind treatment-related weight gain are not fully understood. Endocrine therapies, including estrogen suppression, are associated with hormonal changes that can alter appetite and metabolism. The concern is that reduced estrogen exposure during therapy may contribute to weight gain and fat redistribution over time.
The study design: linking exercise, appetite, and hormones
The Nutrition and Cancer paper details a comparative analysis drawn from two randomized trials involving female breast cancer survivors who were also adults with obesity or high body weight. All participants had been premenopausal before their cancer diagnosis and were currently receiving endocrine therapy. The researchers sought to determine whether sustained physical activity could influence weight outcomes and whether appetite regulation might play a role in any observed effects.
One of the study’s striking findings involves appetite-related hormones. After exercise, participants on estrogen-blocking therapy exhibited higher levels of Peptide YY (PYY), an appetite-suppressing hormone, compared with women without a cancer history. This correlation suggests that exercise might trigger a hormonal response that contributes to appetite control in a population where appetite and energy balance can be disrupted by treatment.
Unpacking the surprising results
What surprised the researchers was that the appetite-suppressing effect persisted beyond the immediate post-exercise window. Despite participants not reporting a subjective drop in hunger, their PYY levels indicated a longer-lasting appetite-regulating response. In practical terms, this means that exercise could help survivors manage how much they eat relative to their body size, potentially slowing weight gain associated with endocrine therapy.
Dr. Purcell emphasizes that the findings are a welcome addition to breast cancer care guidelines, which already advocate for both aerobic activity and resistance or strength training. These activities not only improve cardiovascular fitness and muscle strength but may also improve body composition and metabolic health—key factors for survivors dealing with treatment-related weight changes.
Implications for survivors and clinicians
For survivors, the study reinforces the role of physical activity as a concrete strategy for weight management during and after estrogen-blocking therapy. Tailored exercise programs could be designed to optimize appetite regulation and energy balance, potentially diminishing obesity-related risks and the chance of cancer recurrence associated with weight gain. Clinicians can use this evidence to encourage sustained activity, emphasizing the dual benefits of improved fitness and hormonal modulation that supports appetite control.
While longer-term studies are needed to fully understand the durability of these hormonal responses and how different exercise modalities compare, the current results offer a practical pathway for survivors seeking to manage weight through lifestyle choices. The take-home message is clear: regular exercise may do more than build strength—it could help regulate appetite through hormones in women undergoing breast cancer treatment, contributing to healthier weight trajectories over time.
Practical takeaways for implementing an exercise plan
- Consult healthcare providers to tailor exercise intensity and duration to individual treatment plans.
- Incorporate a mix of aerobic activities (walking, cycling, swimming) with resistance training to support heart health and body composition.
- Monitor weight, appetite cues, and energy levels to adjust activity and nutrition as needed.
- Set realistic goals and seek support from cancer survivorship programs, where available.
