Persistent Cancer-Related Fatigue After Breast Cancer Treatment Predicts Postural Sway and Postexertional Changes in Sit-to-Stand Strategy

Abstract

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is considered a primary mechanism of imbalance among women diagnosed with breast cancer. Recent evidence, however, suggests that cancer-related fatigue (CRF) may also influence balance. Purpose: Examine the contributions of CRF and CIPN to static and dynamic balance before and after a period of fatiguing exercise. Methods: This is a secondary analysis of data examining functional differences between women with breast cancer with and with no persistent CRF. Postural sway was measured during static standing and the rising phase of an instrumented sit-to-stand before and after exercise. Regression analyses were performed to determine how CRF and severity of CIPN predicted sway and how much variance was attributable to each. Results: Greater CRF predicted increased pre-, P = .04, and postexertional, P = .02, static sway in the anterior-posterior plane. Cancer-related fatigue accounted for 10.5% and 9.5% of the variance in pre- and postexertional sway (respectively) compared with the 0.9% and 1.4% accounted for by CIPN severity, which was not a significant predictor. After exercise, greater CRF predicted smaller, more conservative, anterior weight shifting during the instrumented sit-to-stand, P = .01, and accounted for 6.6% of the variance in sway compared with 3% attributed to CIPN, which was not a significant predictor. Limitations: This analysis is limited by its small and demographically homogenous sample. Conclusions: These results suggest that CRF may influence balance independent of CIPN symptoms. While CIPN remains a risk factor for imbalance in this population, CRF warrants consideration in clinical practice and research as a mechanism of postural instability.