Aim of the study: There is little known

about any change in postural balance caused by asymmetrical volume in-crease due to unilateral upper ex-tremity lymphedema in patients who underwent breast surgery. The aim of this study was to determine whether there is a change in postural balance by measuring postural sway velocity (PSV), center of gravity (CoG) displace-ment and directional control (DCL) in patients with unilateral upper extrem-ity lymphedema in breast cancer sur-vivors. Material and methods: Eighteen fe-males 38–60 (M = 53) years old di-agnosed with upper extremity lymph-edema due to breast cancer surgery, and 18 healthy females with similar ages (M = 52.5) were assessed using the Balance Master system (Neuro Com, Clackamas, USA). Unilateral stance (US) and bilateral stance (BS) tests in eyes open and closed condi-tions and the limit of stability (LOS) test were applied to quantify postur-al sway velocity (PSV), CoG displace-ment, and directional control (DCL). Results: The lymphedema group showed a significant increase in PSV in the US test on the ipsilateral leg with eyes open (p = 0.02) and eyes closed (p = 0.005) as well as on the contra-lateral leg with eyes open (p = 0.004) and eyes closed (p = 0.0001). Average displacement and position of the CoG were 25 % of LOS (p = 0.0001) towards the lymphedema side and 60.6 de-grees respectively. DCL in the lymph-edema group was significantly lower in forward (p = 0.0001), back (p = 0.003), ipsilateral (p = 0.002), and contralater-al (p = 0.03) directions. Conclusions: These findings suggest that unilateral upper extremity lymph-edema may have challenging effects on postural balance. Key words: upper extremity, lymphede-ma, postural stability, postural sway, breast cancer