The effect of YOCAS©® yoga for musculoskeletal symptoms among breast cancer survivors on hormonal therapy
Hormonal therapies, such as aromatase inhibitors (AI) and tamoxifen, significantly increase disease-free survival and reduce the risk of recurrence in breast cancer patients [1–3]. However, patients and survivors often experience unpleasant side effects from these therapies including musculoskeletal symptoms (joint pain and stiffness), bone loss, and menopausal symptoms . Phase III trials, using the National Cancer Institute Common Terminology Criteria, indicate that 18–35 % of breast cancer survivors experience musculoskeletal symptoms from AI [5–8]. Studies using survivor reports, however, found that 45–60 % of breast cancer survivors on AI complained of musculoskeletal symptoms [9–12]. Although musculoskeletal symptoms are not widely recognized as a common side effect of tamoxifen, up to 30 % of tamoxifen users report having these symptoms [13, 14]. Musculoskeletal symptoms are a major reason for non-compliance ; up to 25 % of users discontinue usage , representing the number one reason for discontinuation .
Unfortunately, musculoskeletal symptoms in breast cancer survivors on adjuvant hormone treatment are difficult to treat and no standard therapy exists. Survivors have reported achieving pain control with acetaminophen, non-steroidal anti-inflammatory drugs, glucosamine, and opiates . However, there is a paucity of clinical trials demonstrating efficacy. The lack of effective treatments often leads to premature discontinuation, with non-adherence rates ranging between 20 and 40 % [15, 19, 20]. Furthermore, early discontinuation can reduce treatment efficacy and increase mortality .
Yoga is an increasingly prevalent form of exercise in the United States, and is already popular within the breast cancer community. Previous research is limited, but a one-arm trial found yoga reduced joint pain in women on AI , while another study demonstrated qualitative improvements in joint pain with the use of yoga , and a two-arm trial reported yoga participation reduced joint pain in breast cancer patients . Additional studies have shown that yoga improves quality of life in breast cancer survivors, which may be due to reduced musculoskeletal symptoms. Research in non-cancer populations indicated yoga was effective at reducing arthritis pain, back pain, and carpal tunnel pain.