Breast cancer is the most frequently diagnosed cancer among women in the United States, with an estimated 182,460 new cases in 2008 alone.1
Advances in cancer screening and treatment have drastically increased the odds of survival during the past 25 years.2
With this increased life expectancy, breast cancer survivors face new health issues stemming from the treatments for their cancer that were not relevant a few decades ago. For example, secondary osteopenia and osteoporosis, ie, bone loss that is not a direct result of aging but arises from cancer treatment, are major health problems for many breast cancer survivors.3
However, no clinical guidelines for the management of cancer treatment-induced bone loss exist.4
Cancer treatment–induced bone loss affects both premenopausal and postmenopausal breast cancer patients. Chemotherapy has a direct effect on bone health. Breast cancer patients who receive chemotherapy have a significantly lower bone mineral density (BMD) than breast cancer patients who do not receive chemotherapy.5
Chemotherapy also exerts an indirect effect on the skeleton through its effects on the ovaries.6
Premenopausal women who experience ovarian failure as a result of chemotherapy lose up to 7.6% of BMD annually, compared with < 1% for a healthy premenopausal woman. The increase in bone loss among postmenopausal women with breast cancer is primarily attributed to the effects of treatment, namely aromatase inhibitors (AIs) and chemotherapy. In recent years, AIs have been favored among postmenopausal women over tamoxifen because of increased survival and decreased rates of recurrence.7,8
Rates of BMD loss for postmenopausal breast cancer patients receiving AI therapy are significantly greater than for postmenopausal breast cancer patients receiving tamoxifen or a placebo treatment.7–11
On average, postmenopausal breast cancer patients receiving AI therapy tend to lose about 2.6% of their BMD annually, which is more than double the rate of healthy postmenopausal women.12
Research clearly demonstrates that as a result of these life-saving treatments, the bone density of women diagnosed with breast cancer is poorer than the bone density among women of the same age without cancer.
Predictably, BMD loss has led to an increased fracture rate among breast cancer patients. Large, randomized trials of adjuvant hormonal therapy found that those receiving AI were significantly more likely to suffer a fracture than those who did not receive AI.7,10,13,14
Increased fracture risk is not confined solely to those receiving AI. After 5 years of follow-up, those who reported a history of breast cancer in the Women’s Health Initiative had a 31% increase in risk of any clinical fracture, compared with women who reported no history of cancer (P
Kanis et al reported that breast cancer survivors were nearly 5 times more likely to suffer a vertebral fracture than healthy control patients (P
< .05), whereas breast cancer patients with soft-tissue metastases but no bone metastases were almost 23 times more likely to suffer a vertebral fracture.16
The increase in fracture risk can reduce the quality of life for breast cancer survivors.
This decline in BMD and the resultant fractures constitute a major problem for breast cancer survivors because they can interfere with activities of daily living and quality of life. Fractures resulting from osteoporosis have rapidly become a major cause of disability and a public health priority.17
Hip fractures are a major indicator of bone health because their occurrence is closely related to diminished BMD.17
Up to 25% of those who suffer a hip fracture die within 1 year.18
More than 20% of those who experience a hip fracture require long-term care in a nursing facility.19
Those who suffer a hip fracture usually lose the ability to perform daily functions such as climbing stairs, getting dressed, and taking a shower.20
Because of the increasing number of breast cancer survivors and their increased fracture risk, the issue of a decline in quality of life becomes a significant public health issue.
Weight-bearing exercise slows the rate of bone loss across the general population.21,22
Tai Chi Chuan (TCC) is a traditional Chinese martial art that combines slow, circular, fluid movements with deep breathing and relaxation.23,24
Because of its presumed health benefits, safety, and low cost, TCC has become increasingly popular among cancer survivors.25
Tai Chi Chuan may be ideal for preserving bone health in breast cancer survivors because it provides a low-impact form of weight-bearing exercise that is slow and gentle, and improves balance.23,26
Observational studies found that those who regularly practiced TCC had a higher BMD than age-matched counterparts who did not practice TCC.27,28
A few clinical trials used TCC as an intervention to improve bone health in postmenopausal women. One trial demonstrated a significant 2.6-fold to 3.6-fold retardation of bone loss (P
< .01) for those in the TCC arm, compared with those who maintained a sedentary lifestyle.29
Another trial found that those assigned to the TCC arm maintained BMD better than the control group, but the results were not statistically significant.23
In another trial, the effects of TCC were measured according to bone-metabolism biomarkers.30
Six weeks of TCC led to a significant increase in bone-specific alkaline phosphatase (a biomarker of bone formation) compared with the control arm. Recently, cancer patients used TCC as a form of weight-bearing exercise (although it is often considered complementary and alternative medicine) to help manage side effects from cancer treatments.31,32
No clinical trials, to the best of our knowledge, have examined TCC in relation to bone health among women who were diagnosed with breast cancer.
This study sought to examine the effects of TCC on bone health, as defined by bone-metabolism biomarkers, among breast cancer survivors. The change in bone markers over the course of the intervention was calculated and compared between the exercize and control groups. In addition, changes in growth-factor and inflammatory-marker levels were correlated with the change in bone markers, to investigate the underlying biologic mechanism of bone metabolism.