Mobilization of peripheral blood stem cells in patients with advanced thoracic malignancies after irinotecan (CPT-11)...

We evaluated the mobilization of peripheral blood stem cells (PBSCs) after the administration of chemotherapy including irinotecan (CPT-11) in individuals with advanced thoracic malignancies including lung cancer and mesothelioma. All patients were previously untreated. The numbers of CD34+ cells, CD34+ 38- cells, and colony-forming units granulocyte-macrophage (CFU-GM) in peripheral blood were determined to monitor PBSCs at least twice a week. Granulocyte colony-stimulating factor (G-CSF) (75 micrograms/body per day) was administered at the onset of neutropenia [absolute neutrophil count (ANC) of < 1000/microliter] until the ANC exceeded 5000/microliter. In patients who received G-CSF, sufficient counts of the PBSCs for PBSC transplantation were mobilized at the time when the white blood cell count was > 5000/microliter. CPT-11 with G-CSF is thus a promising induction regimen for PBSC transplantation. Patients who did not develop neutropenia after chemotherapy showed a significantly (p = 0.005) higher number of CD34+ cells in the peripheral blood at steady state (median, 1818; range, 1534 to 4433; n = 8) than those who developed neutropenia (median, 666; range, 608 to 1553; n = 5). This parameter may thus prove a useful marker for predicting neutropenia after the administration of CPT-11.