Efficacy of Anti-VEGF/VEGFR Agents on Animal Models of Endometriosis: A Systematic Review and Meta-Analysis

BACKGROUND/OBJECTIVE Vascular endothelial growth factor (VEGF) is the most important promotor of angiogenesis. Some studies indicate that anti-angiogenic agents that interfere with VEGF and its receptor (VEGFR), i.e., anti-VEGF/VEGFR agents, may be applied to treat endometriosis. This meta-analysis investigated the efficacy of anti-VEGF/VEGFR agents in animal models of endometriosis. METHODS A systematic literature search was performed for animal studies published in English or Chinese from January 1995 to June 2016, which evaluated the effect of anti-VEGF/VEGFR agents on endometriosis. The databases were: PubMed, Web of Science, BIOSIS, Embase, and CNKI. The quality of included studies was assessed using the SYRCLE tool. The random-effect models were used to combine the results of selected studies. Heterogeneity was assessed using H2statistic and I2 statistic. Subgroup analyses were performed to determine the source of heterogeneity in endometriosis scores and follicle numbers. RESULTS We identified 13 studies that used anti-VEGF/VEGFR agents in various animal models. The meta-analysis showed that anti-VEGF/VEGFR agents were associated with smaller size (standardized mean difference (SMD) -0.96, 95% CI -1.31 to -0.62; P < 0.0001) and weight (SMD -1.70, 95% CI -2.75 to -0.65; P = 0.002) of endometriosis lesions, relative to the untreated controls, as well as a lower incidence rate of endometriosis (risk ratio 0.26, 95% CI 0.07 to 0.93; P = 0.038) and endometriosis score (SMD -1.17, 95% CI -1.65 to -0.69; P < 0.0001); the number of follicles were similar (SMD -0.78, 95% CI -1.65 to 0.09; P = 0.08). CONCLUSIONS Anti-VEGF/VEGFR agents appeared to inhibit the growth of endometriosis, with no effect on ovarian function. Anti-angiogenic therapy may be a novel strategy in treating endometriosis.