An international team of researchers has identified several risk factors for persistent pain after breast cancer surgery; these include younger age, radiation therapy and removal of lymph nodes under the arm (axillary lymph node dissection), in a new study published in CMAJ (Canadian Medical Association Journal).
The 10-year survival rate for patients with breast cancer is now about 83%. But, between 25% and 60% of women who undergo surgery to remove a tumour develop chronic pain. There is a lack of good-quality evidence about which risk factors predict persistent pain.
To understand the factors associated with chronic postsurgical pain, researchers from Canada, China, Brazil, Spain and Ireland conducted a systematic review of 30 studies with data on 19 813 patients who underwent surgery for breast cancer.
"Our analysis found that women who undergo surgery for breast cancer are much more likely to develop chronic pain if surgeons cut through nerves when performing axillary lymph node dissection to remove their tumor," said Jason Busse, of the Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, Ontario, Canada. "However, we cannot be certain that efforts to spare nerves during breast cancer surgery will prevent development of chronic pain."
Younger age, radiography and acute pain after surgery were also associated with chronic pain. The largest risk factor was axillary lymph node dissection, which was associated with a 21% increase in risk of pain. This procedure is often done during a partial or full mastectomy.
"Although we found a 21% increase in risk for chronic post-surgical pain associated with cutting nerves to access breast tumors, 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. Furthermore, implementing nerve sparing techniques adds extra time to surgery, and that extra time has cost, and possibly complications."
The authors call for more research into risk factors and techniques that may reduce pain.
The study involved researchers from McMaster University, Hamilton, Ontario, Canada; Chinese Cochrane Centre, West China Hospital, Sichuan University, Chengdu, China; University of Toronto, Toronto, Ontario, Canada; University Hospital of Toledo, Toledo, Spain; University School of Medicine, Detroit, Michigan, US; Universidade Federal do Rio Grande do Sul, Porto Alegre, Ro Grande do Sul, Brazil; and University College Cork, Cork, Ireland.