January 2001
EMLA Reduces Acute and Chronic Pain after Breast Surgery for Cancer
Fassoulaki A, Sarantopoulos C, Melemeni A, Hogan Q.
Reg Anesth Pain Med 2000; 25:350-355.

Commentary by Richard W. Rosenquist, M.D.

Many women undergoing common operative procedures for breast cancer, such as modified radical mastectomy or lumpectomy with axillary lymph node dissection alone or in combination with prophylactic chemotherapy and radiotherapy, develop long-term pain syndromes. These are frequently the result of neuropathic injury that produces pain in the chest and/or ipsilateral axilla and/or upper medial arm. This results in significant personal suffering as well as impairment of daily activities. Chronic pain following breast cancer surgery has been estimated to occur in 65% of women age 30-49 years and 40% of women age 50-59 years. It is less common in women over 70 years. Traditionally, the potential development of these pain syndromes postoperatively has not received much attention. Perioperative pain control techniques with the goal of attenuating chronic pain after breast surgery have been uncommon. The authors of this study set out to evaluate the effect of daily EMLA application on acute postoperative pain as well as the chronic pain and sensory abnormalities that occur after breast surgery for cancer.

Forty-six female patients scheduled for breast surgery received randomly 5 g of EMLA or placebo on the sternal area five minutes before surgery, and 15 g on the supraclavicular area and axilla at the end of the operation. Treatment with EMLA cream (20 g) or placebo was also applied daily on the four days after surgery. In the post-anesthesia care unit (PACU), 3, 6, 9 and 24 hours after surgery, and on the second to sixth day postoperatively, pain was assessed by visual analogue scale (VAS) at rest and after movement, and postoperative analgesic requirements were recorded. Three months later, patients were asked if they had pain in the chest wall, axilla and/or medial upper arm, decreased sensation, if they required analgesics at home, and for the intensity of pain.

Acute pain at rest and with movement did not differ between the EMLA and control groups, and the analgesics consumed during the first 24 hours were the same for the EMLA and control groups. However, time to the first analgesia requirement was longer (P = 0.04) and codeine and paracetamol consumption during the second to fifth days was less (P = 0.001, and P = 0.004, respectively) in the EMLA versus the control group. Three months postoperatively, pain in the chest wall, axilla, and the total incidence and intensity of chronic pain were significantly less in the EMLA versus the control group (P = 0.004, P = 0.025, P = 0.002 and P = 0.003, respectively). The use of analgesics at home and abnormal sensations did not differ between the two groups.

The authors concluded that the application of EMLA to patients undergoing breast surgery for cancer reduced the postoperative analgesic requirements and the incidence and intensity of chronic pain.

The neuropathic pain that develops following breast surgery may be the result of injury to the intercostal nerves, or more commonly, the intercostobrachial nerve, and can produce severe persistent neuropathic pain. This may be manifested by an inability to tolerate clothing or even the lightest touch on the anterior chest wall, lateral chest wall, axilla, and upper medial arm. Patients with these pain conditions suffer on a daily basis and frequently the pain has an impact on their activities of daily living as well as their sleep patterns at night. Surgical technique varies widely from institution to institution and in some places careful efforts are made to spare the intercostobrachial nerve and to keep it out of dissection. At other institutions, the intercostobrachial nerve is routinely incorporated into the resection. The ability to truly affect long term outcome and produce a decreased incidence of neuropathic pain, in this case the difference between an incidence of 68% in the control group as compared to 22% in the EMLA group, provides compelling evidence to drive a change in postoperative pain control practice for patients undergoing breast surgery. In an era in which these procedures are often being performed under regional anesthesia via paravertebral block or epidural, the utility of regional analgesia or regional anesthesia as a part of a postoperative pain prevention program would be interesting for future study. In the interval, the importance of understanding the progression of pain from acute to chronic is again emphasized and requires us to look at our own postoperative control practices to see if we may improve the care delivered to this group of patients.