Social Support and Chemotherapy-Induced Peripheral Neuropathy in Breast Cancer: A Full Mediation Dual-Pathway Model...

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating toxicity. While social support is protective, its precise mechanisms remain unclear.

To test whether social support influences CIPN symptoms through physical activity and psychological distress, and if mediation is full or partial.

A prospective cohort of 240 breast cancer patients was enrolled and assessed longitudinally at three time points: baseline, 6 weeks, and 12 weeks. Using structural equation modeling, a partial mediation model (with a direct social support-CIPN path) was compared to a full mediation model (path constrained) via a likelihood ratio test. Indirect effects were tested with bootstrapping.

Model comparison supported the full mediation (Δχ²(1) = 0.22, p = 0.639). Higher baseline social support was associated with greater week-6 physical activity (β = 0.668) and lower week-6 psychological distress (β = -0.602). These mediators subsequently predicted week-12 CIPN symptoms (physical activity: β = -0.403; psychological distress: β = 0.361). Significant indirect effects were found for both the physical activity pathway (β = -0.271) and the psychological distress pathway (β = -0.219). The model explained 47.6% of the variance in CIPN symptoms.

The protective effect of social support on CIPN symptoms operates predominantly by promoting physical activity and buffering psychological distress. These findings support integrated, mechanism-informed interventions leveraging social resources to mitigate a debilitating burden of treatment-related symptoms.