Surgical resection is the best treatment option for colorectal cancer. Despite this radical approach, recurrences within five years are still common. Several authors have proposed that the immunosuppressive state surrounding the perioperative period was a key element of cancer cells spread.

A particular subtype of T lymphocytes, the Natural Killer cells (NKs), is the main actor of the innate immune system. Several factors of the perioperative period can reduce activity of NKs such as stress, pain, opioids and general anaesthetics.

Lidocaine is a local anaesthetic that has been widely used intravenously for abdominal surgeries. Intravenous lidocaine has been shown to reduce pain scores, morphine consumption, ileus time and length of stay in major colorectal surgeries. It reduced markers of systemic inflammation as well.

The authors hypothesize that the use of intravenous lidocaine during laparoscopic surgeries for colorectal cancer resection will preserve NKs activity.

Inclusion Criteria:

• Patients admitted for resection of colorectal cancer under laparoscopic surgery
• American Society of Anesthesiologists class I-III.
• The subject is able to understand the study objectives, the experimental protocol and procedures, and is capable of providing an informed consent.

Exclusion Criteria:

• Subjects allergic to any of the study drugs.
• BMI > 35 kg/m2.
• Severe renal or hepatic failure.
• Pregnancy.
• Emergent procedure.
• Heart failure NYHA > III.
• Systolic blood pressure < 90 mmHg.
• Advanced heart block (unless patient has a pacemaker).
• Unstable angina and/or myocardial infarction within past 6 weeks.
• FEV1 ≤ 0.8 L.
• Oxygen-dependent patient.
• Electrocardiographic abnormalities
• Treatment with immunosupressive drugs, corticosteroids, NSAIDS, antiarythmic
• Morphine intolerance or allergy