Intercostobrachial Nerve Sparing to Reduce Post-Surgical Pain

Overview

Sacrifice of the intercostobrachial nerve (ICBN) during surgery is associated with development of persistent post-surgical pain (PPSP), which affects up to 60% of breast cancer surgery patients. A large, definitive trial is needed to establish whether nerve preservation techniques are effective in reducing post-surgical pain after breast cancer surgery. If the effect of ICBN preservation is consistent with observational studies, the absolute reduction of rates of persistent pain would be considerable.The primary objective is to determine the effect of ICBN preservation, versus usual care, on the prevalence and intensity of PPSP at one year after breast cancer surgery involving axillary lymph node dissection (ALND). Within the larger INSPIRE pilot, we will also be conducting a biomarker sub-study. The objectives of the biomarker sub-study are: 1) to determine the association between pro-inflammatory cytokine levels and the presence and intensity of persistent pain at 3 weeks, and 3 months post-surgery, and) 2) to determine the effect of study intervention on the change in cytokine levels (pre-operative to post-operative) in participants who consent to participate in the sub-study.

A 2016 systematic review that included 30 observational studies (n= 19,813 patients) found high quality evidence that axillary lymph node dissection (ALND) is associated with a 21% absolute risk increase of PPSP (95% CI = 13% to 29%). In many cases of breast cancer, surgery involves axillary approaches; however, preliminary evidence suggests that preservation of the intercostobrachial nerves (ICBN) may reduce the incidence of PPSP after axillary clearance. A 2014 systematic review found 3 small, single-center randomized controlled trials (RCTs), that enrolled a total of 309 patients, and explored the effect of ICBN preservation versus sacrifice during breast cancer surgery. This review found that division of the ICBN was associated with higher risk of sensory deficits, and that nerve preservation techniques increased the median operating time by 5 minutes. Due to limitations of existing evidence, clinical practice guidelines currently provide no recommendations on whether the ICBN should be preserved during axillary lymph node dissection.A large, definitive trial is needed to establish whether nerve preservation techniques are effective in reducing PPSP after breast cancer surgery involving ALND. If all the apparent effect of axillary dissection is associated with lack of ICBN preservation, the absolute reduction of rates of PPSP would be considerable. Furthermore, nerve sparing requires no specialized equipment, suggesting that scalability will be highly feasible. In addition, there is substantial evidence that neuro-inflammation as a result of neural damage leads to peripheral and central changes that can be described as peripheral and central sensitization, leading to PPSP. As such, we will be conducting a biomarker sub-study as part of the pilot program. Identification of biomarkers to correlate with the development of neuropathic pain may facilitate identification of individuals at risk for development of PPSP at an early stage. The INSPIRE trial provides an important opportunity to compare patients before and after nerve injury to further explore the association of persistent pain with cytokine biomarkers. The findings will improve our mechanistic understanding of PPSP.