Pain-related variables as contributing factors to physical activity after breast cancer surgery: a one-year follow-up study.

Physical activity (PA) levels among breast cancer survivors following surgery are often low, with unclear roles played by pain-related factors. This study investigates the changes in PA and its contributing factors, including pain-related factors, in 184 breast cancer survivors throughout the acute post-operative stage of 1 week (T1), the sub-acute stage of 4 months (T4), and the long-term stage of 12 months (T12). A linear mixed model was utilized to evaluate PA changes in the first year post-surgery. Multivariate regression analyses explored associations between moderate-to-vigorous physical activity (MVPA) and patient characteristics, pain-related factors, emotional and physical functioning, and quality of life (QoL) at each timepoint separately and also explored factors in the acute and sub-acute stage contributing to MVPA at T12. Weekly minutes of MVPA and steps had a significant increase between T4 and T12. All models, adjusted for age and BMI, were significant (p < 0.01) but explained only small proportions of variance of MVPA at T1 (AdjR2 :15%), at T4 (AdjR2 :25%) and at T12 (AdjR2 :26%). Pain-related factors, together with emotional and physical symptom burden, negatively impacted PA at various points in time. Despite these challenges, higher QoL and existential well-being were positive influences. Breast cancer survivors demonstrate increasing PA over the first year post-surgery. Contributing factors differ for each timepoint, highlighting the complex interplay of emotional and physical factors in promoting active lifestyles. Rehabilitation interventions need to hold the time-dependency of contributing factors into account and aim to address both immediate and long-term needs.