COX-2 overexpression in peritoneal lesions is correlated with nonmenstrual chronic pelvic pain

ObjectiveTo investigate cyclooxygenase (COX-2) expression within different endometriotic lesions and to assess whether these expression patterns correlate with clinical characteristics.DesignRetrospective cross-sectional study.SettingUniversity Hospital.PatientsSeventy patients with histologically confirmed exclusively peritoneal (n = 20), ovarian (n = 19) or deep-infiltrating (n = 31) endometriosis and a detailed medical history.InterventionImmunohistochemical analysis for COX-2 was performed on 108 endometriotic lesions.Measurements and main resultsCOX-2 intensity, percentage of stained glandular endometriotic cells, and correlation of COX-2 expression with clinicopathological parameters.Semiquantitative COX-2 expression did not differ between distinct morphological types of endometriosis and showed no association with the menstrual cycle. Patients with peritoneal-only endometriosis suffering from moderate or severe chronic pelvic pain showed significantly more frequent COX-2 overexpression than asymptomatic patients or patients with minimal symptoms. In patients with exclusively ovarian or deep-infiltrating endometriosis no association between COX-2 expression and clinical parameters, such as chronic pelvic pain, dysmenorrhoea, dyspareunia, sterility, lower urinary tract symptoms or gastrointestinal symptoms was observed.ConclusionPeritoneal endometriotic lesions with increased COX-2 expression have a special relevance for the development of chronic, nonmenstruation-associated, pelvic pain in endometriotic patients. These patients may benefit from therapy with COX-2 inhibitors.