KINETICS OF MYELOPOIETIC RECOVERY AND MOB ILIZATION OF CD34(-90)() CELLS DURING INTENSIVE CHEMOTHERAPY OF NEUROBLASTOMA (NB)

Hematological and clinical data of 14 children with neuroblastoma trea ted according to the German neuroblastoma therapy study NB 90 were ana lyzed. Therapy included 4 or 8 intensive therapy elements N1 (Etoposid e 125 mg/m(2) day 1-4, Vindesine 3 mg/m(2) day 1, Cisplatin 40 mg/m(2) day 1-4) and N2 (Vincristine 1.5 mg/m(2) day 1 + 8, Dacarbazine 200 m g/m(2) day 1-5, Ifosfamide 1500 mg/m(2) day 1-5, Doxorubicin 30 mg/m(2 ) day 6 + 7) in alternating order. The hematological recovery was stud ied after 86 therapy elements N1/N2. G-CSF had been given in 23 therap y courses, while no cytokine was administered in 63 therapy courses. M obilization of CD34(+) cells was studied in 13 therapy courses with G- CSF. Severe myelosuppression with an absolute neutrophil count < 500/m u L was noted 2-4 weeks after each therapy element. The use of G-CSF d id not prevent, but shortened neutropenia. There was no difference in the number of infections nor time delay of therapy between the courses with or without G-CSF. In 11 therapy courses G-CSF was started on the day following the last chemotherapy dose (N1: day 5; N2: day 9). In 1 2 therapy courses G-CSF was given delayed, starting day 12 after the i nitiation of therapy. Kinetics of granulocyte recovery was similar in the early or delayed application of G-CSF. Neutrophil recovery after t he therapy element N1 was earlier and faster compared to that of thera py element N2. The more rapid rise of the neutrophils after the N1 ele ment was accompanied by an effective mobilization of CD34(+) cells. Ta king into account the limitations of this retrospective study, the dat a may help to optimize the application of G-CSF in a very intensive th erapy study like NB90.