Decline of the Red Blood Cell Count in Patients Receiving Androgen Deprivation Therapy for Localized Prostate Cancer: Impact of ADT on Insulin-like Growth Factor-1 and Erythropoiesis

ObjectivesTo elucidate the mechanism of blood hemoglobin loss in patients with prostate cancer during androgen deprivation therapy (ADT), and to examine the activity of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis during ADT, which plays an important role in hematopoiesis.MethodsA total of 83 patients with localized prostate cancer, who received ADT, were prospectively studied on the basis of their blood samples at the baseline and after ADT for 6 months.ResultsBefore ADT, the IGF-1 level was correlated with the red blood cell (RBC) count (Spearman's rank correlation coefficient analysis [rs]= 0.315, P = .011), hemoglobin (rs = 0.278, P = .018), and mean corpuscular volume (rs = 0.266, P = .020), but such relationships disappeared after ADT. After ADT, the serum IGF-1 level increased compared with that at the baseline (21 ± 6 vs 18 ± 5 nmol/L, respectively, P <.001), but no change was observed in the serum GH level (P = .691). There was no difference between erythropoietin and interleukin-6 concentrations before and after ADT (P = .852 and P = .208, respectively). The hemoglobin concentration and RBC count declined after ADT compared with those before treatment (P <.001 for each). Although the mean corpuscular volume declined after ADT (P = .002), the mean cell hemoglobin was comparable between before and after ADT (P = .676).ConclusionsDespite the unaffected GH, erythropoietin, and interleukin-6 levels, the serum IGF-1 concentration was elevated by ADT. Even with the increased IGF-1 level, the RBC count and hemoglobin concentration declined after ADT. IGF-1 in the bone marrow erythroid progenitor cells might be functionally inactivated during ADT.