Side effects of AIs include an increased risk for developing osteoporosis and joint disorders such as arthritis, arthrosis, and joint pain. The more common adverse events associated with the use of aromatase inhibitors include decreased rate of bone maturation and growth, infertility, aggressive behavior, adrenal insufficiency, kidney failure, and liver dysfunction.
‘Two sessions of weight training and 150 minutes of moderate aerobic activity, such as brisk walking or jogging, every week reduces the effect of Aromatase Inhibitors in breast cancer survivors.’
Gwendolyn Thomas, assistant professor of exercise science, the co-author contends that a combination of resistance and aerobic exercise helps mitigate the side effects of AIs and improves health outcomes in breast cancer survivors, particularly their body composition.
While AIs significantly reduce the risk of breast cancer recurrence, they often lead to bone loss or severe joint pain, known as arthralgia. Hence, many survivors--nearly 40 percent of them, according to one study--stop taking AIs long before their customary five-year treatment period expires.
"When women quit taking AIs, they increase the chances of their breast cancer reoccurring," says Thomas. "If breast cancer survivors are obese or overweight, they are likely to experience arthralgia. Interventions that address obesity in women taking AIs can help them continue this necessary treatment."
Irwin and researchers from Yale, Columbia, Penn State and the Dana-Faber Cancer Institute in Boston led the project, which was the first to examine the effects of aerobic and resistance exercise on postmenopausal breast cancer survivors taking AIs.
Participants did two sessions of weight training and 150 minutes of moderate aerobic activity, such as brisk walking or jogging, every week for a year. The researchers then monitored the participants' body composition, including their body mass index, percent body fat, lean body mass and bone mineral density.
"We noticed a drop in percent body fat and body mass index, as well as a significant increase in their lean body mass. These changes have clinical benefits, but also suggest that exercise should be prescribed in conjunction with AIs, as part of a regular treatment regimen."
It is well documented that breast cancer is the most common cancer diagnosis among American women. Moreover, approximately 65 percent of breast cancer survivors are overweight or obese. Because most breast cancers are hormone receptor-positive (i.e., they use estrogen or progesterone to grow and spread), survivors often rely on hormone therapy, such as AIs, to keep the disease from returning.
Helping breast cancer survivors meet their physical activity goals is what Thomas is working on next. She currently is recruiting participants for a related project, to develop a fitness app for breast cancer survivors.
"By using a mobile platform for health promotion and behavior change, we can make exercise more accessible to breast cancer survivors, especially those who take inhibitors and struggle with obesity or being overweight."
- Gwendolyn Thomas et al., Researcher examines effect of exercise on breast cancer survivors, Obesity Journal (2017).