Swiss Multi-centre, Randomized, Placebo Controlled Trial of Pregabalin for Prevention of Persistent Pain in High Risk Patients Undergoing Breast Cancer Surgery

BACKGROUND Persistent postsurgical pain occurs in more than 30% of patients undergoing breast cancer surgery. Evidence that gabapentinoids such as pregabalin may reduce the incidence of persistent postsurgical pain is ambiguous, potentially because in previous trials prophylactic treatment was administered to every patient undergoing surgery. The patients at low risk of long term pain, were exposed to side effects without much benefit to expect. AIM Validating or refuting the utility of pregabalin to prevent long term post-operative pain in patients at high risk of persistent pain after breast cancer surgery. METHODS Randomized, double-blind, placebo-controlled trial of pregabalin (2\*150mg from the day before breast cancer surgery until 2 weeks after surgery) in patients at high risk of persistent pain (\>30%). High-risk patients are identified by a risk score derived from a previous observational study. The main outcome is the incidence of clinically important pain (necessitating analgesic treatment, or having an intensity of \>3 at rest or \>5 on movement) at 3 months after surgery. Secondary outcomes are: incidence of neuropathic pain, pain interference, and incidences at 6 and 12 months of follow-up. In addition, side effects of pregabalin and the retention rate during the treatment period will be monitored, as well as patient expectancies. RELEVANCE This is the first study for prevention of persistent postoperative pain which targets only high-risk patients, thus lowering a false negative outcome and averting the risk of side effects for patients at low risk. The study is powered to show a reduction of the incidence of clinically important pain at 3 months of 20%. In the case the study shows that this can be achieved and pregabalin is well tolerated, the preventive use of pregabalin for breast cancer surgery would be justified at least in high-risk patients. On the other hand, a negative result would indicate the futility of pregabalin prevention, which is already in routine use in many hospitals.