Ultrasound Guided Pecs Block and Ketamine Infusion for Preventing Chronic Pain in Patients Undergoing Breast Cancer Surgery

Inclusion Criteria: * Adult female patients with breast cancer aged between 18-75 years * ASA (American Society of Anesthesia) physical status I, II, and III * Patients scheduled for elective breast cancer surgery (Mastectomy with or without axillary clearance) Exclusion Criteria: * Refusal to participate or withdrawal of informed consent * Surgical procedures involving breast reconstruction with flaps or implants * Patient scheduled for bilateral mastectomy * Reoperation on the same side due to cancer recurrence * Known allergy or contraindication to study drugs * History of severe psychiatric illness (e.g., major depression, bipolar disorder, schizophrenia) * Chronic opioid use, substance abuse, or opioid addiction * Pre-existing chronic pain or neuropathic pain disorders * Coagulopathy, anticoagulation therapy, or localized infection at the site of block * Uncontrolled hypertension and ischemic heart disease