Study population~All of patients will undergo mastectomy with or without immediate breast reconstruction.~230 patients will be enrolled.~Intervention~OFA group will be sedated using dexmedetomidine and lidocaine.~Conventional opioid anesthesia group will be sedated using remifentanil.~Pain screening~Breast Cancer Pain Questionnaire (BCPQ)~Pain-detect, HADS, EQ-5D, PHQ-15 (somatic symptom), PCS (pain catastrophizing), BFI (big five inventory), HAM-A&D, Pressure algometry (Pain sensitivity), Quantitative sensory test (pinprick)
In 230 patients undergoing mastectomy, the investigators will compare opioid-free anesthesia (OFA) versus conventional opioid-based anesthesia in terms of chronic pain. The enrolled patients will be randomly assigned into two groups with 1:1 ratio. Chronic pain will be evaluated at 1 year after mastectomy based on the Breast Cancer Pain Questionnaire (BCPQ). Baseline pain sensitivity test and psychologic evaluation will be done before operation.