Anesthetic strategies in oncological surgery: Not only a simple sleep, but also impact on immunosuppression and cancer recurrence

Tumor recurrences or metastases remain a major hurdle in improving overall cancer survival. In the perioperative period, the balance between the ability of the cancer to seed and grow at the metastatic site and the ability of the patient to fight against the tumor (i.e. the host antitumor immunity) may determine the development of clinically evident metastases and influence the patient outcome. Up to 80% of oncological patients receive anesthesia and/or analgesia for diagnostic, therapeutic or palliative interventions. Therefore, anesthesiologists are asked to administer drugs such as opiates and volatile or intravenous anesthetics, which may determine different effects on immunomodulation and cancer recurrence. For instance, some studies suggest that intravenous drugs, such as propofol, may inhibit the host immunity to a lower extent as compared to volatile anesthetics. Similarly, some studies suggest that analgesia assured by local anesthetics may provide a reduction of cancer recurrence rate; whilst on the opposite side, opioids may exert negative consequences in patients undergoing cancer surgery, by interacting with the immune system response via the modulation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system, or directly through the opioid receptors on the surface of immune cells. In this review, we summarize the main findings on the effects induced by different drugs on immunomodulation and cancer recurrence.