The inclusion criteria were: :  age 18-65 years at the time of recruitment. candidates for curative surgery for breast cancer. American Society of Anaesthesiologists (ASA) status I/II.  The exclusion criteria were:  ASA status > II. counter-indications for use of the drugs employed in this protocol. pregnancy or lactation. incapacity to understand the study explanation and sign the informed consent form.  These criteria were selected according to the risk mitigation strategy described in the protocol.