Analysis of hematological parameters as prognostic markers for toxicity and survival of 223 Radium treatment.

223 Radium (223 Ra) has emerged as treatment prolonging survival in patients with metastatic castration-resistant prostate cancer (CRPC). As 223 Ra can cause hematotoxicity (HT), pre-existing hematopoiesis might influence the efficacy of 223 Ra and the rate of hematotoxicity, but as to our knowledge such data has not been published yet, we retrospectively conducted an analysis on patients receiving 223 Ra. 54 patients treated with 223 Ra had a median survival of 67 weeks, which was significantly reduced in patients with pre-existing Hb toxicity (Tox) grade 2 (48 weeks P = 0.008) as compared to grade 1 (67 weeks) and normal levels of Hb (not reached); survival in patients with Plt Tox grade 1 was significantly reduced (44 weeks) as compared to normal Plt counts (71 weeks, P = 0.033). Patients with impaired hematopoiesis regarding Hb and Plts developed significantly more grade 3 and 4 HT (Hb < 10 g/dl: 42.9% [3/7] vs 10.6% [5/47], P < 0.001; Plt < 150 G/L: 28.6% [2/7] vs 6.4% [3/47], P = 0.002) and received significantly fewer treatment cycles (Hb <10 g/dl: 5.1 vs 5.8, P = 0.04; Plt < 150 G/L: 3.4 vs 5.6, P < 0.001). These results imply that pre-existing impaired hematopoiesis, in particular thrombocytopenia and anemia, before 223 Ra therapy, is an important risk factor for worse outcome of treatment with 223 Ra.