Exercise may reduce side effects of breast cancer drugs

A combination of weight training and moderate aerobic exercise - such as brisk walking or jogging - may mitigate the side effects of drugs used to reduce breast cancer recurrence risk, a new study has found.
Aromatase Inhibitors (AIs) or hormone-therapy drugs reduce the risk of breast cancer recurrence, but they often lead to bone loss or severe joint pain, known as arthralgia.
Hence, many survivors - nearly 40 per cent 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 re-occurring," said Gwendolyn Thomas from the Syracuse University in the US.

"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," said Thomas who conducted the research at Yale Univsersity.
For the study, 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 participant's body composition, including their body mass index, per cent body fat, lean body mass and bone mineral density.
"We noticed a drop in per cent body fat and body mass index, as well as a significant increase in their lean body mass," said Thomas.

"These changes have clinical benefits, but also suggest that exercise should be prescribed in conjunction with AIs, as part of a regular treatment regimen," she said.
It is well documented that breast cancer is the most common cancer diagnosis among American women. Moreover, about 65 per cent of breast cancer survivors are overweight or obese.
Since most breast cancers are hormone receptor-positive - they use estrogen or progesterone to grow and spread - survivors often rely on hormone therapy, such as AIs, to keep the disease from returning.
AI treatment, however, can be a double-edged sword because of the aforementioned effects that are not connected to age-related decline.

"These changes put women at risk for frailty fractures and osteoporosis, not to mention further risk for comorbid chronic disease and cancer reoccurrence," said Thomas.
The study appears in Obesity Journal.