Perioperative period is critical in determining the risk of postoperative metastatic disease. Surgical damage and related stress response could suppress cell-mediated immunity and facilitate malignant cell survival, motility, invasion and proliferation. Increasing evidence supported that the continuous infusion of lidocaine or dexmedetomidine, or intrathecal morphine were associated with the reduction of postoperative pain and opioid consumption and improved the quality of recovery.~Also, they were reported to decrease perioperative inflammatory responses and preserve immune response which is known to be critical in anti-metastatic process during perioperative period. However, no comparison was conducted among these anesthetic adjuvants. Thus, Investigators try to evaluate the effect on the biomarkers and clinical outcomes in the three methods.
This is a prospective randomized controlled trial. Investigators aimed to compare the effect of three different anesthetic adjuvants (continuous infusion of lidocaine or dexmedetomidine, intrathecal morphine injection) on the biomarker for cancer recurrence and metastasis.~Patients undergoing elective colorectal cancer surgery will be randomly allocated to three parallel arms and the biomarkers for cancer recurrence and metastasis, inflammation, and immune response will be compared. And we will compare the clinical outcomes in the three method.