(RxWiki News) Occasionally, studies of medical data find unexpected trends. Recently, an analysis of anesthetic use during liver surgery found a surprising relationship for tumor recurrence.
A study of medical records over a nine-year period revealed that general anesthesia was associated with fewer recurrence of tumors in liver cancer.
But despite the difference, there was no significant difference in mortality between the two groups.
"Ask your surgeon about minimally invasive surgery."
A group from China studied whether anesthetic technique made any difference in a specialized surgery known as radiofrequency ablation, where surgeons use radio waves rather than scalpels to destroy tumors. Radiofrequency ablation may be used for surgery in difficult areas to access, or when a minimally invasive technique is preferred.
Documented by Renchun Lai, M.D., of Sun Yat-Sen University Cancer Center in Guangzhou, the recurrence of liver tumors was lower in patients who had regional anesthesia instead of general anesthesia.
Dr. Lai examined the outcomes of 179 patients who underwent radio frequency ablation for small liver tumors, comparing general anesthesia in 117 patients to epidural anesthesia in 62.
The authors of the study called for randomized clinical trials to investigate further for the true cause of the relationship between anesthesia use and reduced tumor recurrence. Theories ranged from a direct effect of the anesthesia on the tumor cells or even the immune system itself, but the finding could reflect decisions by surgeons on which anesthesia to use on a case by case basis.
"Such retrospective studies are very difficult to interpret because it is impossible to understand what risk factors were not evenly distributed among the patients," commented Steven L. Shafer, M.D., of Columbia University, Editor-in-Chief of Anesthesia & Analgesia.
Other professionals believed that the anesthesia itself could be the cause. "There is overwhelming mechanistic support for regional analgesia protecting against cancer recurrence, along with strong animal data," commented Daniel I. Sessler, M.D., chair of Outcomes Research at The Cleveland Clinic.
"We and others have published both positive and negative retrospective studies. But all are small and suffer all the substantial limitations of observational analyses. Resolution of the question will have to await the results of randomized trials, including ours."
A separate study published in 2005 found that the costs of regional and general anesthesia were similar overall, with some variations of 10 percent in either direction depending on the characteristics of the individual surgery.
Results were published in the journal Anesthesia & Analgesia. Authors of the study declared no conflict of interest.