RESUMEN
Opioids are the main group of pharmacological agents used during the perioperative period and provide a sedative and analgesic component. The observations of opioid consumption in West Europe indicate that this group of drugs is widely used in chronic noncancer pain therapy. Nearly 20 years ago, the first publications indicating that opioids, as an element of perioperative pharmacotherapy in oncologic patients, increase the risk of tumor recurrence and affect further prognosis were presented. The actual publications suggest that there are multifactorial, complex mechanisms underlying the immunological impact and carcinogenesis promotion of opioids and that the intensity varies depending on the type of opioid. There are also questions about the immunosuppressive effects among patients receiving opioids in the treatment of chronic noncancer pain. The aim of the review article is to present information about the action of opioids on the immune system in carcinogenic settings and to define the clinical usefulness of this pharmacological phenomenon.