Introduction: Women with breast cancer are often prescribed
aromatase inhibitors, which can cause rapid loss of bone mass leading to
significant potential for morbidity. Vibration training has been shown to be
helpful in reducing bone turnover in postmenopausal women without cancer.
Aim: To examine the effect of vibration stimulus on markers of
bone turnover in breast cancer patients receiving aromatase inhibitors.
Methods: Thirty-one breast cancer survivors undergoing
treatment with aromatase inhibitors were randomized to vibration stimulus (n =
14) or usual care control (n = 17). Low-frequency and low-magnitude vibration
stimulus (27-32 Hz, 0.3g) was delivered in supervised sessions
via standing on a vibration platform for 20 minutes, 3 times per week for 12
weeks. The primary outcome was blood markers of bone resorption (serum
N-telopeptide X/creatine) and formation (serum type 1 procollagen N-terminal
propeptide; P1NP). Other study outcomes body composition as well as measures of
physical functioning. Outcomes were compared between groups using analysis of
covariance adjusted for baseline values as well as time on aromatase inhibitors.
Outcomes: On average, participants were 61.5 years old and
overweight (ie, body mass index = 28.5 kg/m2). Following vibration
training, there was no significant difference between groups for bone resorption
(adjusted group difference 0.5, P = .929) or formation
(adjusted group difference 5.3, P = .286). There were also no
changes in any measure of physical functioning body composition.
Conclusions: Short-term low-magnitude vibration stimulus does
not appear to be useful for reducing markers of bone turnover secondary to
aromatase inhibitors in breast cancer patients; nor is it useful in improving
physical function or symptoms. However, further investigations with larger
samples and higher doses of vibration are warranted. Trial
Registration: Australian and New Zealand Clinical Trials Registry
(ACTRN12611001094965).