For postmastectomy neuropathic pain, perineural infiltration with a combination of bupivacaine and dexamethasone is a “simple, effective, practice-changing treatment that any surgeon can do,” according to Laura J. Esserman, MD, MBA, Professor of Surgery and Radiology at the University of California, San Francisco, School of Medicine and Director of the Carol Franc Buck Breast Care Center, senior author of the study.
The intervention—2-mL injections of an equal ratio of 0.5% bupivacaine and 4 mg/mL of dexamethasone—was described at the 2013 San Antonio Breast Cancer Symposium.1 The study’s first author was Cathy J. Tang, MD, also a surgeon at the University of California, San Francisco.
Study Rationale
Some 20% to 68% of breast cancer patients have chronic postoperative breast pain, commonly known as postmastectomy pain syndrome. Usually this is neuropathic in origin and can begin in the immediate postoperative period, but may appear 6 months postoperatively or later. It often persists beyond the normal healing period, sometimes years.
The study’s hypothesis was that T4 and T5 sensory nerves are damaged—cut and cauterized—during surgery, and this is the source of the pain. Such trauma can lead to neuroma formation and cause postoperative pain along the specific dermatomes.
“We go in and find the maximal point of tenderness, usually at 6 o’clock or 9 o’clock along the intramammary fold,” Dr. Esserman told The ASCO Post. “We take a mixture of bupivacaine and dexamethasone and inject this at the site of the neuroma, where the T4 and T5 nerves likely exit the chest wall. We wait half a minute, and then massage it in. Within a minute, the patient has no more pain. For 60% of patients, we never have to inject again.”
Outcomes Data
Since January 2011, Dr. Esserman and her colleagues have treated and tracked 19 patients who presented with characteristic neuropathic pain and point tenderness located at either the inframammary fold directly inferior to the nipple or laterally along the midaxillary line. Patients were followed from 6 to 25 months.
The 19 patients received 29 total injections, and pain resolved in 93% of the injection sites. For 17 patients (59%), only one injection was required. For 10 (34%), pain resolved after multiple injections. In one patient (3.5%), an injection was scheduled but had not occurred yet, and for another patient (3.5%) who had pain after stereotactic biopsy, the pain did not resolve, possibly because the location of the neuroma was not well targeted.
The study also emphasizes the need for careful dissection of the T4 and T5 sensory nerves to avoid cauterizing the nerve along with the accompanying blood vessels, thus avoiding postoperative neuroma formation, which clearly contributes to postmastectomy pain, the authors said.
Dr. Esserman said that surgeons and nurses should routinely ask about postoperative focal neuropathic pain, which can also exhibit as the inability to wear a bra or to lie on the affected side.
“This condition affects patients’ daily lives. It can be miserable, and it is much more common than surgeons think,” she said. “If you are taking care of a patient and have given her chronic pain, that’s a terrible thing that you have to pay attention to.” ■
Disclosure: Dr. Esserman reported no potential conflicts of interest.
Reference
1. Tang CJ, Elder SE, Lee DJ, et al: 2013 San Antonio Breast Cancer Symposium. Abstract P3-10-03. Presented December 12, 2013.
