Prognostic Value of Hemoglobin in Metastatic Hormone-sensitive Prostate Cancer: A Systematic Review and Meta-analysis.

The purpose of this study was to assess the prognostic value of hemoglobin (Hb) in patients with metastatic hormone-sensitive prostate cancer (HSPC). The PUBMED, Web of Science, Cochrane Library, and Scopus databases were searched in December 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Studies were deemed eligible if they compared patients with HSPC with normal and low Hb levels to determine their ability to predict overall survival, cancer-specific survival, progression-free survival, and castration-resistant prostate cancer-free survival. Formal meta-analyses were performed for these outcomes. The systematic review identified 25 studies including 6614 patients; 21 studies comprising 5782 patients were eligible for meta-analysis. Low Hb levels were associated with worse overall survival (pooled hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.15-1.29), cancer-specific survival (pooled HR, 1.46; 95% CI, 1.24-1.72), progression-free survival (pooled HR, 1.21; 95% CI, 1.14-1.28), and castration-resistant prostate cancer-free survival (pooled HR, 1.37; 95% CI: 1.18-1.57). Subgroup analyses revealed that low Hb levels were also associated with poor overall survival in patients with both "high-volume" (pooled HR, 1.49; 95% CI, 1.29-1.72) and "low-volume" HSPC (pooled HR, 1.40; 95% CI, 1.13-1.73). This meta-analysis revealed that low Hb serum levels in patients with metastatic HSPC were associated with increased risks of overall mortality, cancer-specific mortality, disease progression, and biochemical recurrence. Furthermore, Hb levels were independently associated with overall survival in the "high-volume" and "low-volume" HSPC subgroups. Therefore, it might be useful to incorporate Hb testing into prognostic tools for metastatic HSPC.