Anemia is associated with poor outcomes of metastatic castration-resistant prostate cancer, a systematic review and meta-analysis.

Androgen deprivation therapy (ADT) was an important management for metastatic prostate cancer. However, patients would finally progress to the metastatic castration-resistant prostate cancer (mCRPC) and lose sensitivity to ADT. In addition to lower testosterone level, ADT could cause anemia, which might impair the chemotherapy efficiency and worsen the outcomes of cancer patients. However, inconsistent results were found between anemia and mCRPC prognosis. Our study was the first systematic review to evaluate the influence of anemia in mCRPC prognosis. Thirteen studies with 6,484 samples were involved in this meta-analysis. We found anemia would worsen the Overall survival (OS) of mCRPC patients in both prognostic designed studies (HR = 1.55, 95% CI = 1.24-1.94) and retrospective designed studies (HR = 1.82, 95% CI = 1.52-2.18). Prognostic analyses also demonstrated that anemia associated with poor Progression free survival (PFS) (HR = 1.47, 95% CI = 1.22-1.75). In conclusion, we found that anemia was significantly associated with poor OS and PFS of mCRPC patients. Larger RCTs are needed for future study, especially for the evaluation of treatment value for anti-anemia in mCRPC.