Surgical treatment of breast cancer is frequently associated with postoperative pain in the surgical area. Persistent pain after breast cancer management has considerable negative effects on the quality of life of survivors. The aim of this trials is to evaluate the efficacy of thoracic paravertebral block with bupivacine 0.5% in reducing the acute pain postmastectomy compare with surgical wound infiltration with bupivacaine 0.5%.

Surgical treatment of breast cancer is frequently associated with postoperative pain in the surgical area, restricted movement of the ipsilateral upper limb and increased risk of chronic pain. This usually occurs even though management with analgesics commonly used in the postoperative period. Properly treatment of acute postoperative pain have essential implications: improving the general welfare of patients, can better withstand future medical interventions, facilitating recovery in the short and long term and is believed to have positive impact on survival from cancer.

Persistent pain after breast cancer management has considerable negative effects on the quality of life of survivors. Several risks factors have been described in preoperative, intra-operative and postoperative periods of persistent or chronic pain. In the postoperative period the most important risk factor is the severity of acute pain. For this, pain relief is an essential component of care of patients undergoing breast cancer surgery. Current evidence suggests that treatment of acute postoperative pain reduces the risk of persistent or chronic pain syndrome. The surgical wound infiltration with local anesthesia has been used routinely in patients managed at the Cancer Institute and Clinica Las Americas and is described as a safe and accessible procedure for the management of acute postoperative pain. Paravertebral block represents an interesting alternative in the management of perioperative pain, often used for breast surgery, hernia repair and thoracotomy in children and adults. Although complications associated with blocking are uncommon, the implementation of Ultrasound-guided approach has become the standard for performing said method.

Such considerations have led us to evaluate whether patients with breast cancer who are undergoing mastectomy, thoracic paravertebral block could be better in relief acute pain in comparison with surgical wound infiltration with local anesthesia. This will be studied by controlled randomized to one of two intervention groups (paravertebral block or local anesthesia with infiltration of the surgical wound) allocation trial. In all patients, general anesthesia and routine postoperative analgesic is used.

Inclusion Criteria:

1. Women older than 18 years.
2. Diagnosis of breast cancer requiring major elective surgery: unilateral mastectomy with or without axillary dissection; with or without axillary sentinel node biopsy; with or without immediate breast reconstruction.
3. Willingness to participate in the study during the follow-up period.

Exclusion Criteria:

1. Metastatic breast carcinoma; tumor involvement of contra lateral breast or armpit determined by clinical or paraclinical studies.
2. Medical History of coagulopathy.
3. Consumption of anticoagulants.
4. Contraindication to NSAIDs or opioids.
5. Allergy to local anesthetics of amide type.
6. Infection a interventions sites (paravertebral block or area affected breast surgical wound)
7. Pregnancy and lactation.
8. BMI>35.
9. Parkinson's disease, Alzheimer's disease or other diseases that affect the mental or motor sphere.
10. Double mastectomy or mastectomy history of previous ipsilateral to the current episode.
11. Preoperative risk classification ASA IV-V.