Return of chronic pelvic pain from endometriosis after raloxifene treatment - A randomized controlled trial

OBJECTIVE: To evaluate whether 6 months of raloxifene was effective in treatment of chronic pelvic pain in women with endometriosis. METHODS: Women with chronic pelvic pain and no endometriosis treatment for 6 months underwent laparoscopy for excision of all lesions. Those with biopsy-proven endometriosis were randomly allocated to raloxifene (180 mg) or placebo daily. A second laparoscopy was performed at 2 years, or earlier, if pain returned. Return of pain was defined as 2 months of pain equal to or more severe than that at study entry. Menstrual cycles and adverse events were recorded. The log rank test was used to compare the time to return of pain by drug group. Analyses were done as intent-to-treat. RESULTS: A total of 127 of 158 women underwent surgery. Of these, 93 had biopsy-confirmed endometriosis and were randomly assigned to study treatment, Menstrual cycle length, pelvic pain severity, quality of life, bone mineral density, and adverse events did not differ between treatment groups. The Data Safety Monitoring Committee terminated the study early when the raloxifene group experienced pain (P=.03) and had second surgery (P=.016) significantly sooner than the placebo group. Interestingly, biopsy-proven endometriosis was not associated with return of pain (P=.6). CONCLUSION: Raloxifene significantly shortened the time to return of chronic pelvic pain. Because recurrence of endometriosis lesions did not correlate with return of pain, other factors are implicated in pelvic pain. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www. clinicaltrials.gov, NCT00001848.