An evidence-based medicine approach to the treatment of endometriosis-associated chronic pelvic pain: placebo-controlled studies

OBJECTIVE: Use an evidence-based medicine (EBM) approach to evaluate the evidence regarding efficacy of treatment of endometriosis-associated chronic pelvic pain (CPP) in placebo-controlled randomized clinical trials (RCT). DESIGN: Review of six randomized, controlled trials (Canadian Task Force classification I). SETTING: University of Rochester School of Medicine and Dentistry. Patients. Three hundred eighty-one women with endometriosis enrolled in placebo-controlled randomized clinical trials. Intervention. A MEDLINE search of published medical articles from January 1976, to January 1998. MEASUREMENTS AND MAIN RESULTS: Six placebo-controlled randomized clinical trials were found that addressed the treatment of pelvic pain associated with endometriosis and met validity criteria; one was a study of surgical treatment, two of medical therapies, and three of combined surgical and medical treatments. They clearly show that laparoscopic surgery and medical treatment with medroxyprogesterone acetate, danazol, or nafarelin are more effective than placebo. Evidence for efficacy of leuprolide acetate is weaker. At 6 months, absolute decreases in pain scores are quite similar with surgical or medical treatment. Medical therapy after surgical treatment significantly reduced pain, but six months after it was stopped there was no difference between women treated and not treated postoperatively. CONCLUSIONS: Although either surgical or medical treatment of endometriosis in women with CPP is clearly indicated, pain relief of 6 or more months' duration can be expected in only 40 to 70% of women with endometriosis-associated CPP.