Secondary Erythrocytosis Produced by the Tyrosine Kinase Inhibitors Sunitinib and Sorafenib

myeloablative conditioning regimen and 80% of the patients in the RIC group. In the myeloablative group (n 79), 39 patients (49%) received the combination of cyclophosphamide plus TBI, 18 patients (23%) received busulfan plus cyclophosphamide, and 22 patients (28%) received other chemotherapy-containing protocols. In the RIC group (n 89), the vast majority of the patients received allograft with fludarabine-containing regimens: fludarabine plus melphalan, 30 patients (33%); fludarabine plus cyclophosphamide, 23 patients (26%); fludarabine plus busulfan, 12 patients (13%); and other combinations, nine patients (10%). Only seven patients (8%) received lowdose TBI in the conditioning regimen. Although the number of patients treated with low-dose TBI was low, all of them experienced relapse after transplantation and died as a result of disease progression. Intensity of conditioning regimen seems to be important, taking into account the heavily pretreated and sometimes refractory population of patients who are included in allogeneic protocols, as has been indicated by others. 5