This single-center randomized controlled trial aims to investigate the effects of adding scapulothoracic stabilization and postural training to standard lymphedema care in women with secondary upper extremity lymphedema following breast cancer surgery. Participants will be randomly assigned to receive either standard lymphedema care alone or standard care combined with scapulothoracic stabilization and postural training. Outcomes including scapular muscle strength, posture, upper extremity function, limb volume, and neck awareness will be assessed at baseline, immediately after treatment, and at a 2-month follow-up. The findings are expected to provide evidence regarding the effectiveness of incorporating targeted stabilization and postural exercises into conventional lymphedema rehabilitation.