The prognostic value of vascular endothelial growth factor in ovarian cancer: a systematic review and meta-analysis.

OBJECTIVE: The prognostic role of vascular endothelial growth factor (VEGF) in ovarian cancer remains inconclusive. This meta-analysis aimed to explore the association between VEGF overexpression and survival outcomes in ovarian cancer patients.
METHODS: Studies were identified from PubMed and EMBASE searches performed on January 2nd, 2011. After careful review, survival data were extracted from eligible studies. A meta-analysis was performed to generate combined hazard ratio (HR) for progression-free survival (PFS) and overall survival (OS) in serum and tumor tissue studies.
RESULTS: Sixteen studies with 1111 patients were analyzed. Elevated serum VEGF was significantly associated with poor PFS [HR 2.46, 95% CI (1.84, 3.29)] and OS [HR 2.21, 95% CI (1.57, 3.13)]. No significant heterogeneity existed in serum studies. Similarly, tissue VEGF overexpression was associated with poor PFS [HR 1.63, 95% CI (1.09, 2.42)] and OS [HR 1.70, 95% CI (1.01, 2.87)]. However, significant heterogeneity was found in tissue studies, with I(2) of 44% for PFS and 64% for OS. Studies were stratified into subgroups by International Federation of Gynecology and Obstetrics (FIGO) stages. Subgroup analyses showed that high tissue VEGF was significantly associated with shorter PFS [HR 5.34, 95% CI (1.95, 14.59)] and OS [HR 6.13, 95% CI (2.47, 15.26)] in studies where predominantly early-stage patients were included, but not in studies with a majority of advanced-stage patients. Subgroup analysis was not performed in serum studies because all those studies enrolled more patients in advanced stages than early stages.
CONCLUSIONS: Overexpression of VEGF in primary tumor and serum associates with poor PFS and OS for patients with ovarian cancer. The association between high tissue VEGF level and poor prognosis exists in early stage patients, but not in advanced stage patients.