Paravertebral block could save lives of women with breast cancer undergoing mastectomy
The use of paravertebral block with anaesthetic propofol in women with breast cancer undergoing mastectomy lowers the rate of cancer recurrence and five-year mortality compared with women receiving volatile anaesthetics, according to a recent study presented at the annual meeting of the American Society of Anesthesiologists.
The authors urge for the use of paravertebral blocks should be considered in these patients even if it requires obtaining training in ultrasound-guided regional anesthesia.
Stuart A. Grant, MB ChB, a professor of anesthesiology at Duke University Medical Center, in Durham, N.C., and colleagues examined the records of 1,083 patients undergoing total unilateral or bilateral mastectomies for breast cancer at their institution; patients were only included if they had at least five years of follow-up. The investigators compared patient demographics, tumour characteristics, anaesthetic method, treatment modality, disease recurrence rate and mortality.
The patients were divided into three groups based on the anaesthetic technique used:
- volatile anaesthetic without regional analgesia (n=648),
- volatile anaesthetic plus paravertebral block (n=141), and
- monitored anaesthesia care using propofol infusion with a paravertebral block (n=294).
"This is not the first study of its kind; others have done it before," said Dr Grant. "However, they were usually underpowered to demonstrate any effect and didn't follow their patients up for very long."
"It's important to note that the propofol–the paravertebral group is not opioid-free," Dr Grant told Anesthesiology News. "We still need some painkiller afterwards, and they often get 50 mcg of fentanyl for block placement."
Dr Grant also explained that preliminary univariate analysis revealed some marked differences between patient groups. "It was interesting because our propofol–the paravertebral group had more stage III or IV tumours than did the other groups, and also had more lymph node–positive tumours. So when you look at our initial data, you would imagine that the propofol–paravertebral patients should have a higher chance of recurrence."
Key findings of the study include:
- Paravertebral block with propofol was found to improve cancer recurrence rate compared with general anaesthesia alone.
- Paravertebral block with propofol also proved superior to general anaesthesia plus the block.
- Patients who received the paravertebral block with propofol also benefited in terms of mortality, which was significantly lower than among patients receiving general anaesthesia alone.
- There was no significant mortality benefit when the two groups that received the paravertebral block were compared.
- In multivariate analysis, age was identified as an independent risk factor for mortality.
Also Read: Type of anesthesia not linked to breast cancer recurrence rate, finds study
As Dr Grant discussed, the techniques used in the paravertebral block with propofol patients may have played a role in the lower cancer rates in this study. "We use a very high concentration of local anaesthetic in our block," he said. "We also combined the block with propofol, which on its own has been shown to have benefits in terms of cancer recurrence compared to a volatile anaesthetic.
"I think that makes a difference at the time of surgery when there can be marked tumour spread through the vascular system," Dr. Grant said. "Normally, the vascular system is a very hostile environment for cancer cells. Giving people volatile anaesthetics and opioids makes that environment a lot friendlier for those cells to spread. But high-dose local anaesthetic is systemically absorbed, which makes it much more difficult for tumour cells to metastasize."
Given these findings, the investigators believe the paravertebral block with propofol approach should be the anaesthetic method of choice for women undergoing a mastectomy. "The question is this: can we afford to not use this approach?" Dr Grant asked. "What would you want if it was your wife, mother or sister?"
Although mastering this technique may once have been challenging, it is far simpler in the age of ultrasound guidance, he noted. "If you're determined to learn the paravertebral block, it's certainly something that can be taught to any practitioner, and the complication rate is extremely low."
Nevertheless, the researchers recognized the limitations of their retrospective trial and await the results of prospective randomized trials on the topic. "In the meantime, this is a really strong and powerful indicator," Dr Grant said. "I really think there's a signal here that what we do during cancer anaesthesia can make a difference."