Prognostic significance of preoperative serum albumin in epithelial ovarian cancer patients: a systematic review and dose-response meta-analysis of observational studies

Purpose: To comprehensively assess the impact of preoperative serum albumin levels on survival of patients with epithelial ovarian cancer (EOC). Materials and methods: Two independent researchers searched the PubMed, Embase, and Web of Science databases to identify relevant studies from inception to October 20, 2017. The studies were independently reviewed and those deemed eligible were selected based on predetermined selection criteria. Summarized HRs and 95% CIs were calculated for overall survival (OS) with a profile likelihood random-effects model. Results: Twelve cohort studies comprising 3884 EOC patients were included for analysis. Comparison of the highest vs the lowest categories of preoperative serum albumin yielded a summarized HR of 0.63 (95% CI= 0.45-0.88, I-2= 88.8%). Although the results were robust in all subgroup analyses stratified by International Federation of Gynecology and Obstetrics (FIGO) stage, cutoff definition, geographical location, quality of study, number of EOC cases, followup time, and adjustments made for potential confounders, not all were statistically significant. Of note, dose-response analysis showed that for each 10 g/L increment in preoperative serum albumin level, the summary HR was 0.56 (95% CI= 0.35-0.92, I-2= 78.6%). No evidence of publication bias was detected by funnel plot analysis and formal statistical tests. Sensitivity analyses showed no important differences in the estimates of effects. Conclusion: The present meta-analysis suggests that preoperative serum albumin can be used as an independent prognostic predictor of OS in EOC patients. Since the included studies had high heterogeneity and retrospective designs, these results require further validation with prospective cohort trials enrolling larger patient populations with longer follow-up examinations.