(RxWiki News) Most breast cancers are treated with surgery to remove either the tumor or the breast itself. Either operation requires some form of anesthesia to numb the body from pain and put the patient to sleep. New research suggests the type of anesthesia used during breast cancer surgery may affect outcomes.
A recent study found that the use of a technique called a nerve block, which numbs nerves in a specific region of the body, during breast cancer surgery decreased the risk of cancer returning and spreading four-fold.
Patients who received the nerve block, along with general anesthesia, were more likely to be alive six years after the surgery than patients who had received general anesthesia only, according to the study.
This small study also found that patients who had nerve blocks needed less opioid (strong narcotic) pain relief than patients who had general anesthesia.
"Ask your surgeon about the type of anesthesia you’ll be given."
Palle S. Carlsson, MD, PhD, of the Department of Anesthesiology at Aarhus University Hospital in Denmark, led this study to look at the long-term effects of anesthesia methods used during breast cancer surgery and pain medications used after the operation.
Dr. Carlsson explained that during surgery, cancer cells can escape and enter the blood stream where they can travel to lymph nodes or other organs. The immune system protects against these rogue cells, but anesthesia and the surgery itself can weaken the immune system.
This study was a follow-up to a randomized, double-blind study (neither patients nor physicians knew what was being given) looking at paravertebral blocks (regional anesthesia nerve blocks) in 77 patients who had undergone breast cancer surgery.
The patients, all of whom had received general anesthesia, were randomly divided into two groups.
One group of 39 patients received a regional nerve block that was given in four to six injections of a local anesthetic in the upper back to one side of the spine.
The other group of 38 patients received injections of saline solution, which does nothing.
The researchers reviewed the medical records of study members six years later and found that both recurrence (return of cancer) and death rates were substantially lower in the patients who’d had the nerve blocks.
Of the patients who had a nerve block, 10 percent had died six years after surgery, compared to 32 percent of those who had been given general anesthesia only.
A total of 13 percent of patients in the nerve block group saw their cancers return while 37 percent of the patients receiving only general anesthesia had a recurrence of breast cancer.
Additionally, the need for opioid pain relief was lower in the patients whose cancer did not return. They required an average of 45 milligrams of morphine, compared to the 58 milligrams of morphine needed by patients whose cancer returned.
“Our findings bring increased evidence to the hypothesis that paravertebral block through [lessening] of surgical stress and reduced opioid consumption reduces the risk of developing metastases,” the authors concluded.
"The study is small but intriguing," Rob Fuller, MD, surgical oncologist with Capital Surgeons Group in Austin, Texas, told dailyRx News.
"That degree of survival difference is very significant, but the rationale that it is due to less opioid use may be true, but the difference of opioid use between the two groups is modest at best. There may be other reasons for the difference as yet not determined but it does lend support to a larger multi institutional study to fully confirm these findings," Dr. Fuller said.
Findings from this study were presented at the Anesthesiology 2013 annual meeting.
It should be noted that research is considered preliminary before publication in a peer-reviewed journal.