Cancer-related fatigue a common adverse effect of breast cancer chemotherapy

Pennsylvania [United States], August 20 : Cancer-related fatigue (CRF) is a long-term side effect of chemotherapy for breast cancer that contributes to chronic balance difficulties.
The study's findings were published in Rehabilitation Oncology, the official publication of the American Physical Therapy Association's Oncology Academy (APTA). Wolters Kluwer also publishes the journal as part of the Lippincott portfolio.
The current study, led by Stephen Wechsler, PT, DPT, PhD, of the MGH Institute of Health Professions in Boston, is the first to measure and compare CRF's contribution to postural instability to chemotherapy-induced peripheral neuropathy (CIPN). "Our findings...indicate that CRF, even years after chemotherapy exposure, may distinctly impact balance regardless of a patient's CIPN status," the researchers write.
Greater postural sway and variations in the 'sit-to-stand' function are predicted by CRF.
Many people who have had breast cancer face physical or functional restrictions, such as balance issues and an increased risk of falling. These balance issues are commonly related to CIPN, which is nerve damage that frequently happens as a side effect of cancer treatment. Recent research suggests that CRF, another prevalent side effect of cancer and its treatment, may potentially contribute to balance issues.
Dr Wechsler and colleagues examined data from 43 women who had chemotherapy for breast cancer to investigate the link between CRF and postural instability. Patients were followed for an average of 3.5 years following cancer therapy. Consistent with the high reported frequency of CRF, the average tiredness score was 43 on a scale of 0 to 100, with higher scores indicating more exhaustion. CIPN symptoms were present in more than half of the women (53.5%).
Participants were subjected to a battery of standardised balancing function tests. Women with higher CRF scores showed more anteroposterior (front to back) postural sway in a static (standing still) balance test. After controlling for other variables, the CRF score accounted for around 10% of the variance in postural sway, compared to 1% for CIPN.
After a brief exercise activity, those with more severe CRF showed higher postural sway. Postural sway was not associated with the severity of CIPN in either test.
Further studies looked at the effects of CRF on dynamic balance during a typical sit-to-stand test, which is a crucial indicator of physical functioning and a predictor of fall risk. In this test, CRF accounted for over 7% of the variation in postural sway following a fatiguing exercise targeting the muscles of the lower extremities, compared to 3% for CIPN.
Participants with higher CRF demonstrated "smaller, more cautious" forward movements in body weight during the sit-to-stand test after exercise. This trend is consistent with a "stabilisation technique" found in people with balance issues. The stabilisation method, according to Dr Wechsler and colleagues, is symptomatic of weak postural control since it depends more on lower leg strength than the "momentum transfer" strategy found in those with higher balance functions.


The researchers explore many therapeutic implications of their findings, including the possibility that a lower-extremity-fatiguing job may create or worsen deficiencies in dynamic balance in CRF survivors. Survivors may experience such tiring tasks in their daily lives by completing activities of daily living, navigating stairs or the neighbourhood, or participating in a suggested fitness programme.
The findings complement to prior research demonstrating that CRF after chemotherapy and other treatments may lead to balance issues and an increased risk of falling in breast cancer survivors. "While CIPN remains a risk factor for imbalance in this group," Dr Wechsler and colleagues write, "CRF bears investigation in clinical practise and research as a cause of postural instability."
The findings might have an impact on how rehabilitation experts prescribe exercise to cancer survivors, particularly in terms of increasing dynamic balance to lower the chance of falling. Patients with CRF following cancer treatment, in particular, "may benefit from balance-related instruction regarding safety and coping or compensating methods," the researchers write.