Cutting nerves during breast cancer surgery is associated with chronic pain

CMAJ published their review of studies exploring risk factors for developing chronic pain after breast cancer surgery which also included younger age and radiation therapy.

"Ten-year survival rates for breast cancer patients are now around 83%, but up to 60% of women who undergo surgery as part of cancer treatment, may develop chronic pain," said senior author Jason Busse. He is an assistant professor of anesthesia, and a researcher with the Michael G. DeGroote Institute for Pain Research and Care at the Michael G. DeGroote School of Medicine.

The international research team, led by Dr. Busse's postdoctoral student, Dr. Li Wang, conducted a systematic review that analyzed 30 observational studies that enrolled 20,000 women undergoing surgery for breast cancer. Analysis of this data suggested that disruption of sensory nerves in the axilla (armpit) as lymph nodes are removed is associated with the development of chronic pain.

"We cannot be certain that efforts to spare nerves during axillary surgery for breast cancer will prevent development of chronic pain," Busse added. "Although we found a 21% increase in risk for chronic post-surgical pain associated with axillary node surgery, nerve sparing may not always be possible, and when possible may not reduce the risk of chronic pain as much as the current evidence suggests."

Changes are being made around the world to change treatment, said Dr. Susan Reid, an author on the study. She is also professor and chair of surgery at McMaster's Michael G. DeGroote School of Medicine and a breast cancer surgeon.

"Current standards in axillary surgery have already undergone a significant shift towards sentinel node biopsy, which lessens all potential complications for many patients," she said.

Busse noted that large, well-conducted randomized trials are needed on the issue.