“The present results are consistent with the theory that peridural analgesia may improve survival by decreasing the immunosuppressive effects of surgery and general anesthesia,” they comment in the Annals of Surgery online April 26.
The authors explain that previous studies have suggested that patients with various types of cancer benefit from peridural analgesia during surgery, but it is unclear if this includes colorectal cancer patients.
To investigate, Dr. Marco Gruss, at Klinikum Hanau GmbH in Hanau am Main, and colleagues analyzed data recorded in a prospective cancer registry on 749 patients who underwent surgery for colorectal cancer from 2003 to 2009.
After consultation with an anesthesiologist, 442 of the patients opted to have a peridural catheter placed for pain control during surgery and postop; the other 307 patients declined or had contraindications.
Overall, 5-year survival rates were 62% among patients who received peridural analgesia compared to 54% among those who did not (p=0.02). After adjustment for confounding variables, this translated to a mortality hazard ratio of 0.73 for patients who received peridural analgesia.
However, the survival benefit was confined mainly to patients with greater medical morbidity, the team found. That is, survival was significantly greater for patients with American Society of Anesthesiologists (ASA)classification 3-4 (p <0.009) but not for patients with ASA grade 1-2.
“Patients who have increased morbidity (ASA classification 3 to 4) may be more susceptible to impairment of the immune system and these patients may benefit the most from the effects of peridural analgesia in reducing the immunosuppressive effects of surgery,” Dr. Gruss and colleagues suggest.
Summing up, they conclude, “The finding that peridural analgesia may improve long-term survival in patients with cancer is of great clinical interest and warrants further randomized controlled trials.”