Opioids and tumour metastasis: does the choice of the anesthetic-analgesic technique influence outcome after cancer surgery?

PURPOSE OF REVIEW: Cancer is now one of the leading causes of death worldwide, and excisional surgery is an essential treatment for the four most common adult cancers. Opioids remain the most commonly prescribed analgesics in the perioperative period of cancer surgery, yet the question of whether opioids could influence recurrence or metastasis remains unanswered. RECENT FINDINGS: In-vitro cell culture, live animal models, and retrospective clinical reviews investigating the effects of opioids on outcomes after cancer surgery have yielded conflicting results, with findings ranging from deleterious, null to potentially protective effects. SUMMARY: Prospective randomized trials are required to investigate this important topic further. Several are currently ongoing. Until the results of these are available for scrutiny, there is currently insufficient evidence to recommend any changes to current clinical practice. Opioids continue to play an important role in the perioperative period.