August 15, 2022 – For many women who have undergone chemotherapy for breast cancer, cancer-related fatigue (CRF) is a persistent side effect, and one that contributes to ongoing balance problems, suggests an article in Rehabilitation Oncology, the official journal of APTA Oncology, an academy of the American Physical Therapy Association (APTA). The magazine is published in the Lippincott portfolio by Wolters Kluwer.
New research by Stephen Wechsler, PT, DPT, PhD, of the MGH Institute of Health Professions, Boston, and colleagues is the first to quantify and compare the relative contribution of CRF to postural instability versus neuropathy chemotherapy-induced peripheral neuropathy (CIPN). “Our results … indicate that CRF, even several years after exposure to chemotherapy, can clearly influence balance regardless of a patient’s CIPN status,” the researchers write.
CRF predicts greater postural sway and changes in sitting function
After breast cancer treatment, many patients experience physical or functional limitations, such as balance problems and an increased risk of falls. These balance problems are often attributed to CIPN—nerve damage that often occurs as an adverse effect of cancer chemotherapy. However, recent studies have suggested that CRF, another common side effect of cancer and its treatment, may also contribute to balance problems.
To examine the relationship between CRF and postural instability, Dr. Wechsler and colleagues analyzed data from 43 women who had undergone chemotherapy for breast cancer. Patients were studied an average of 3.5 years after cancer treatment. Consistent with the reported high frequency of CRF, the mean fatigue score was 43 on a scale of 0 to 100, with higher scores indicating greater fatigue. More than half of the women (53.5%) had at least mild symptoms of CIPN.
Participants underwent a series of standardized assessments of balance function. In a static (standing) balance test, women with higher CRF scores had increased anteroposterior (front-to-back) postural sway. After adjusting for other factors, the CRF score accounted for about 10% of the variation in postural sway compared to 1% for the CIPN.
Women with more severe CRF also had increased postural sway after a brief exercise task. In both tests, postural sway was not significantly related to CIPN severity.
Further trials assessed the effects of CRF on dynamic balance during a standard sit-to-stand test, a key measure of physical functioning and a predictor of fall risk. In this test, after fatiguing exercise targeting lower limb muscles, CRF accounted for almost 7% of the variance in postural sway compared to 3% for CIPN.
After exercise, participants with greater CRF showed “smaller and more conservative” forward shifts in body weight during the sit-up test. This pattern is consistent with a “stabilization strategy” commonly seen in people with balance problems. Dr. Wechsler and colleagues point out that the stabilization strategy suggests impaired postural control because it relies more on lower leg strength, compared to the “momentum transfer” strategy observed in people with better balance function.
Impacts of cancer-related fatigue
The researchers discuss several clinical implications of their findings, most notably that a fatiguing task in the lower extremities may cause or exacerbate impairments in dynamic balance among CRF survivors. Survivors may encounter these fatiguing tasks in daily life by performing activities of daily living, negotiating stairs or the community, or participating in a recommended exercise program.
The report adds to recent studies suggesting that CRF after chemotherapy and other treatments may contribute to balance problems and the risk of falls in breast cancer survivors. “Although CIPN remains a risk factor for imbalance in this population, CRF warrants consideration in clinical practice and research as a mechanism of postural instability,” concluded Dr. Wechsler and co-authors.
The findings may have implications for rehabilitation professionals who prescribe exercise for cancer survivors, particularly with regard to improving dynamic balance to reduce the risk of falls. In particular, patients with CRF after cancer treatment “may benefit from balance-related education regarding safety and coping or compensatory strategies,” the researchers add.
Click here to read “Persistent cancer-related fatigue after breast cancer treatment predicts postural changes and post-exercise changes in the sit-to-stand strategy”
DOI: 10.1097/01.REO.0000000000000308
/ Public communication. This material from the original organization/author(s) may be ad hoc in nature, edited for clarity, style and length. The views and opinions expressed are those of the author(s). See them in full here.