Author: Michael Vlessides
Compared with the use of volatile anesthetics, total IV anesthesia (TIVA) may offer long-term protective effects following breast cancer surgery.
A new systematic review and meta-analysis concluded that patients undergoing TIVA with propofol had lower rates of cancer recurrence and higher rates of recurrence-free survival. However, there was no significant difference between groups in overall mortality.
“The impetus for this meta-analysis was to look at differences in outcomes after cancer surgery, and whether that difference depends on the type of anesthesia,” said Zhaosheng Jin, MBBS, a research fellow at Stony Brook University School of Medicine, in Stony Brook, N.Y.
“Breast cancer is one of the most common cancers, and going forward, a lot of the surgical caseload is going to be cancer-related,” Dr. Jin continued. “So, I think this is something that is potentially going to have a big impact in terms of how many patients it will affect.”
Effect May Be Organ- or Mutation-Specific
As Dr. Jin reported at the 2019 annual meeting of the International Anesthesia Research Society (abstract F014), the literature search found 130 studies comparing TIVA with volatile anesthesia in breast cancer surgery. Of these, five studies were ultimately included (Ups J Med Sci 2014;119:251-261; Oncotarget 2017;8:90477-90487; Korean J Anesthesiol 2016;69:126-132; BMC Anesthesiol2018;18:131; Anesthesiology 2019;130:31-40).
“Because of the nature of the intervention, most of the included studies were retrospective,” Dr. Jin said in an interview with Anesthesiology News. “Most of them were studies that compared propofol with sevoflurane, but we included studies with any volatile anesthetic.”
All five studies reported mortality rates, with follow-up periods ranging from two to five years. Nevertheless, the meta-analysis did not find a significant difference in mortality between patients who underwent TIVA or volatile anesthesia (hazard ratio [HR], 1.14; 95% CI, 0.92-1.40).
Three studies reported the rate of cancer recurrence. This outcome was better for TIVA (combined HR, 0.62; 95% CI, 0.40-0.96).
Finally, two studies reported the rate of recurrence-free survival, which again favored TIVA (combined HR, 1.18; 95% CI, 1.01-1.38).
For Dr. Jin, the meta-analysis is a first step toward shining some light on a question that has puzzled anesthesiologists for years. “We didn’t really know what to expect,” he said. “Laboratory studies seem to favor propofol slightly, but there are clinical studies that go both ways. So, we went into it not really knowing which would come out on top.”
Nevertheless, the study demonstrated that propofol may indeed offer some advantages over volatile anesthetics in breast cancer surgery.
“I think the exact effect is likely very organ-specific, cancer-specific and mutation-specific,” Dr. Jin said. “Ultimately, the aim is that one day we can personalize anesthesia to the point where we test a patient’s biopsy sample beforehand and actually find out his or her cancer responds to anesthesia, which could then be used to plan the anesthetic care of the patient.”
The investigators also noted that, although the results of the meta-analysis are promising, they need to be validated in large clinical trials.
Wanted: Large International Trial
Daniel I. Sessler, MD, told Anesthesiology News that the theory that anesthesia might influence cancer recurrence is intriguing. “There are compelling in vitro and animal results suggesting that it might, but compelling evidence in humans is lacking and nearly all observational,” said Dr. Sessler, the Michael Cudahy Professor and chair of the Department of Outcomes Research at the Cleveland Clinic, in Ohio.
“One large observational trial suggests that propofol-based intravenous anesthesia might be protective for large operations, and another showed no benefit for breast cancer, which usually causes considerably less tissue disruption and surgical stress than abdominal surgery,” Dr. Sessler noted. “To the extent that intravenous anesthesia might be protective, it is most likely to show benefit for large operations.
“At this point, additional observational analyses are unlikely to answer the question. Major trials are needed,” Dr. Sessler said. “Fortunately, a large international trial comparing total intravenous and volatile anesthesia for major surgery, led by Bernhard Riedel [the director of the Department of Anesthesia, Perioperative and Pain Medicine at Peter MacCallum Cancer Centre in Melbourne], will start enrolling patients next year.”