This single-center, parallel-group randomized controlled trial (RCT) will compare two timings for initiating specific exercise therapy after breast cancer surgery. The study tests whether early initiation (within the first postoperative week) versus delayed initiation (at 3 weeks postoperative) results in superior upper limb function at 6 months as measured by the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. Secondary outcomes include pain intensity (Visual Analog Scale, VAS) and wound-related complications such as drainage time and hematoma incidence.