Prognostic role of cyclooxygenase-2 in epithelial ovarian cancer: A meta-analysis of observational studies

Objective. The aim of this study was to evaluate the prognostic significance of cyclooxygenase-2 (COX-2) on survival in patients with ovarian cancer by using a meta-analysis of observational studies. Methods. We searched Pubmed and Embase to retrieve observational studies evaluating the association between COX-2 status and survival in patients with ovarian cancer. Hazards ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were pooled across studies using a random-effects model. Results. A total of 17 studies were included in this meta-analysis to estimate the association between COX-2 and overall survival (OS), disease-free survival (DFS), response to chemotherapy (RC), and other clinical parameters. In a random-effects meta-analysis of 15 studies, higher COX-2 expression significantly predicted poor OS (death HR, 1.34; 95% CI, 1.05-1.71; I-2 = 56.5%). A more prominent association was found between COX-2 expression and poor OS when studies with adjustment for age, stage, and histology were included (death HR, 1.65;.95% CI, 1.25-2.17; I-2 = 0%). However, higher COX-2 expression was not significantly associated with poor DFS (recurrence HR, 1.36; 95% CI, 0.79-2.33; I-2 = 53.6%) and RC (OR, 1.89; 95% CI, 0.85-4.21; I-2 = 17.6%). There was a marginally significant association between COX-2 positivity and several clinical parameters such as age, stage, and histology. The pooled ORs of higher COX-2 expression were 1.75 (95% CI, 1.01-3.04) for advanced stages, 1.34 (95% CI, 0.97-1.85) for old age, and 1.42 (95% CI, 0.98-2.05) for serous cancer in histologic type, respectively. Conclusions. The present meta-analysis suggests that higher COX-2 expression may be an independent risk factor for poor OS in patients with ovarian cancer. (c) 2013 Elsevier Inc. All rights reserved.