Comparison of peripheral blood progenitor cell yield from standard chemotherapy used in the treatment of lymphoid malignancies and high-dose cyclophosphamide: a retrospective review of 141 patients

BACKGROUND: Peripheral blood progenitor cells (PBPCs) are often collected after mobilization with high-dose cyclophosphamide (HDC) combined with growth factors. HDC may not be needed for PBPC mobilization, and patients with lymphoid malignancies can be harvested with treatment regimens of chemotherapy. STUDY DESIGN AND METHODS: A retrospective analysis was performed on 141 patients with lymphoma or multiple myeloma whose PBPCs were harvested after chemotherapy. The PBPC yield and time to mobilization was compared between patients who received HDC (n = 51) and other chemotherapy regimens (n = 90) including high-dose cyclophosphamide and etoposide (HDC plus VP-16; n = 41), CHOP, ESHAP, ABVD, VAD, and others (n = 49). A multiple linear regression model and proportional hazards model determined factors influencing yield and time to mobilization, respectively. RESULTS: The difference in mean yield between HDC and all non-HDC regimens was significant, with HDC plus VP-16 resulting in the highest yields. The proportion of patients achieving a CD34 count in excess of 5 x 10(6) per kg did not differ significantly between the regimens. In a multiple linear regression model, HDC plus VP-16 resulted in a higher PBPC yield than HDC but all other regimens did not. In addition, patients exposed to more than one prior chemotherapy regimen had lower yield regardless of the mobilization regimen. The mean number of days to mobilization with HDC was 10.2 days, 17.1 days for HDC plus VP-16, and 14.2 days for all other regimens. The timing of mobilization was influenced by the chemotherapy used and the number of prior regimens in a proportional hazards model. CONCLUSION: These results demonstrate a higher mean yield of PBPCs with HDC plus VP-16 but no difference in yield between non-HDC plus VP-16 regimens used for first-line or relapse therapy and HDC, suggesting that HDC may be an unnecessary additional therapy.