**6. Conclusions**

Multiple clinical studies suggest that both anesthesia and surgery induce immunosuppression that can promote tumor recurrence through locoregional growth and distant spread; undesirable circumstance that reduces the survival of our patients and impoverishes their prognosis.

We believe that the anesthetic plan should include immunoprotective actions that fully cover the entire perioperative period. Among them we highlight minimizing the response to psychological and physiological stress, through medical stability and adequate pre, intra and postoperative analgesia.

An anesthetic-surgical technique that minimizes tissue injury, reduces bleeding and reduces the risk of blood transfusion will be beneficial in order to reduce tumor progression.

Although the evidence on the influence of anesthetic drugs on tumor progression is limited, it can be stated, based on recent experimental and clinical studies, that the use of anesthetic/analgesic techniques that reduce the perioperative consumption of opiates such as morphine, as well as other drugs with a proven negative profile, such as ketamine, are favorable to protect the anti-metastatic immune response in a period of special pro-tumor susceptibility such as the perioperative period.

We propose anesthetic techniques combined with the use of regional anesthesia and analgesia, preferring them to those based on the use of opioids and halogenated agents, since it has been shown that situations that determine greater activation of the SNS and the HPA axis, promoting a pro-inflammatory state, will generate a negative alteration of immunity with the consequent higher rate of tumor recurrence.

Therefore, based on current evidence and our experience, we recommend the use of supported analgesic/anesthetic techniques based on regional anesthetic blocks prior to surgical aggression, complemented by the administration of NSAIDs, dipyrone, paracetamol, and anesthetic maintenance with propofol. As well as an adequate management of psychological stress, the maintenance of normothermia and techniques that reduce the risk of blood transfusions in the perioperative period are related to the preservation of immunity and therefore with better results in cancer patients.
