Following exposure to breast cancer chemotherapy, cancer-related fatigue contributes to balance issues.
Cancer-related
fatigue (CRF) is a common side effect of chemotherapy for breast cancer
patients and is linked to continued balance issues, according to a study
published in Rehabilitation Oncology, the official journal of APTA Oncology, an
academy of the American Physical Therapy Association (APTA). Wolters Kluwer
publishes the journal under the Lippincott imprint.
The
MGH Institute of Health Professions, Boston, and colleagues' recent study is
the first to quantify and contrast the relative contributions of
chemotherapy-induced peripheral neuropathy and CRF to postural instability
(CIPN).
The
researchers conclude that their findings "suggest that CRF, even years
after exposure to chemotherapy, may distinctly impact balance regardless of a
patient's CIPN status."
Greater
postural sway and modifications to "sit-to-stand" function are
predicted by CRF.
Many
breast cancer patients develop physical or functional restrictions after
treatment, including balance issues and a higher risk of falling. These balance
issues are commonly related to CIPN, a common side effect of cancer
chemotherapy that causes nerve damage. Recent research, however, indicates that
CRF, another typical side effect of cancer and its treatment, might also be
related to balance issues.
Data
on 43 women who had received chemotherapy for breast cancer were examined by
Dr. Wechsler and colleagues to determine the connection between CRF and
postural instability. A median of 3.5 years had passed since cancer treatment
when patients were evaluated. The average score for fatigue was 43 on a
0-to-100 scale, with higher scores indicating more fatigue, which is consistent
with the high reported frequency of CRF. The majority of the women (53.5%)
experienced some degree of CIPN symptoms.
A
series of standardised evaluations of balance function were performed on the
participants. Women with higher CRF scores showed more anteroposterior (front to
back) postural sway during a static (still) balance test. After adjusting for
other variables, the CRF score explained 10% more variation in postural sway
than the CIPN, which only explained 1%.
Following
a brief activity assignment, postural sway was also more pronounced in those
with more severe CRF. Postural sway did not substantially correlate with the
severity of CIPN in either test.
Additional
studies looked at how CRF affected dynamic balance during a sit-to-stand test,
a crucial indicator of physical health and a predictor of the likelihood of
falling. In this test, CRF accounted for over 7% of the variance in postural
sway compared to 3% for CIPN following an exhausting workout that targeted the
muscles of the lower extremities.
During
the sit-to-stand test after exercise, persons with higher CRF displayed
"smaller, more conservative" forward transfers in body weight. That
pattern fits with a "stabilisation technique" frequently observed in
people with balance issues. According to Dr. Wechsler and colleagues, the
stabilisation method, which depends more on lower leg strength than the
"momentum transfer" strategy seen in persons with higher balance
function, is symptomatic of inadequate postural control.
Cancer-related
Fatigue's Effects
The
most important clinical relevance of the study's findings is that
lower-extremity-fatiguing tasks may contribute to or exacerbate dynamic balance
abnormalities in CRF survivors. Performing routines of daily living, navigating
stairwells or the neighborhood, or taking part in a suggested exercise regimen
can all present survivors with such taxing challenges.
The
study supports recent research that suggests CRF following chemotherapy and
other therapies may increase breast cancer survivors' risk of falling and balance
issues. While CIPN continues to be a risk factor for imbalance in this
population, Dr. Wechsler and co-authors suggest that CRF should be taken into
account in clinical practice and research as a mechanism of postural
instability.
The results could have an impact on how rehabilitation specialists recommend exercise to cancer survivors, especially in terms of increasing dynamic balance to lower the chance of falling. The researchers note that individuals with CRF who have had cancer treatment "may benefit from balance-related instruction regarding safety and coping or compensatory measures."