A Study to Reduce Persistent Post-mastectomy Pain Using Opioid-free Anesthesia (RELIEF)

A Single-blinded Randomized-controlled Study to Reduce Persistent Post-mastectomy Pain Using Multimodal Opioid-free Anesthesia

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.

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)

Control arm: Conventional Anesthesia with opioid Interventional arm: Opiod-free Anesthesia with dexmedetomidine and lidocaine

Presence of chronic pain will be assessed by Breast Cancer Pain Questionnaire (BCPQ). Zero score means absence of persisting breast-related pain. The minimum and maximum values of pain scale are 0 and 11, respectively. High score means worse outcome.

Presence of anxiety and depression symptoms will be assessed by HADS (Hospital Anxiety and Depression Scale) questionnaire. The range of each symptoms scale is between 0 and 21. A scale of 0-7 is defined as normal, a scale of 8-10 is defined as borderline, and a scale of 11-21 is defined as abnormal. High score means worse outcome.

The type of pain will be assessed by painDetect Questionnaire (PDQ). The PDQ comprises 12 items. The first three assess current pain, strongest pain during the past 4 weeks, and average pain during the past 4 weeks on a 0-10 point numerical rating scale from "none" to "worst imaginable".

Inclusion Criteria: All of patients will undergo mastectomy with or without immediate breast reconstruction. Exclusion Criteria: Previous history of breast surgery Allergy to drug Other cancer history Underlying psychologic disorder Patients with chronic pain requiring pain killers Baseline SpO2 <95% Left ventricular EF <40% Bradycardia as HR <50 bpm BMI >35kg/m2 Pregnant woman