There has been great interest recently in the possibility that the anesthetic technique for oncological surgery may influence long-term survival by modulating immune function in the perioperative period.
Dr. Juraj Sprung, Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota, and colleagues from the United States and Singapore compared the outcomes of patients undergoing radical prostatectomy for cancer anesthetized with either general anesthesia (GA) and opioids postoperatively or epidural anesthesia (without GA) and epidural fentanyl postoperatively. The results of their study are discussed in this month’s issue of Anesthesia and Analgesia in the article titled “Outcomes After Radical Prostatectomy for Cancer: A Comparison Between General Anesthesia and Epidural Anesthesia with Fentanyl Analgesia: A Matched Cohort Study.”
Four hundred eight-six men who underwent prostatectomy under epidural anesthesia between 1991 and 1996 were closely matched with patients who had GA with systemic opioids. The investigators considered four outcomes: prostate cancer recurrence, systemic cancer progression, prostate cancer mortality, and all-cause mortality. The median follow-up times were 16 and 15 years in the epidural and GA groups respectively.
There were no significant differences between the anesthetic techniques for the four outcome measures. In other words, there was no benefit from epidural anesthesia/analgesia. The authors suggest that the “failure” of epidural analgesia was a consequence of the prolonged infusion of epidural fentanyl after surgery (median dose >4 mg). Epidural fentanyl is rapidly absorbed into the circulation and is therefore not “opioid sparing,” which the authors argue is a major factor in improving perioperative immunosuppression.
This article complements a paper recently published in the British Journal of Anaesthesia by the same group of investigators in which they compared the outcomes after radical prostatectomy with either GA and systemic opioids or neuraxial blockade, predominantly spinal analgesia with bupivacaine and morphine. Again, this was a matched cohort study with a 9-year median follow-up. In contrast to epidural fentanyl, neuraxial blockade was associated with a significantly decreased risk of systemic progression of cancer and overall mortality, but there was no benefit in terms of cancer recurrence and prostate cancer death. The investigators ascribe the improvement in outcomes in this study to the opioid-sparing effect of spinal anesthesia/analgesia.
Matched cohort studies have limitations readily acknowledged by the authors, but they indicate fertile areas for future research. The avoidance of large doses of opioids postoperatively is already an integral part of many multimodal analgesic regimens designed to expedite recovery after major surgery. It is possible that the benefits may extend to improved outcomes after cancer surgery. This is an important contribution to a “hot” topic that is still in its investigative infancy.