Ideal body weight correlates better with engraftment after PBSC autograft than actual body weight, but is under-estimated in myeloma patients possibly due to disease-related height loss

Abstract

Stem cell dose is important in determining rate of engraftment following autograft. We show closer correlation with haematopoietic reconstitution when the CD34 þ cell dose is calculated using ideal (IBW) rather than actual (ABW) body weight in 218 patients receiving peripheral blood stem cell (PBSC) autograft for haematological malignancy. ABW was 21% greater than IBW thus the median CD34 þ dose of 5.0 Â 10 6 /kg (ABW) rose to 6.1 Â 10 6 /kg when calculated by IBW. Neutrophils reached 0.5 Â 10 9 /l in 11 days (range 8-21), while platelets reached 20 Â 10 9 /l unsupported in 12 days (range 7-38). For both neutrophil and platelet engraftment, a greater inverse correlation was seen when IBW was used to calculate stem cell dose (r 2 ¼ 0.082 vs r 2 ¼ 0.104 for neutrophils and r 2 ¼ 0.085 vs r 2 ¼ 0.135 for platelets). Those non-myeloma patients who failed to achieve a CD34 þ dose of 4 Â 10 6 cells/kg by ABW but did so by IBW achieved neutrophil and platelet engraftment not significantly different from those who achieved that stem cell dose by both methods. This was not confirmed in patients treated for myeloma, possibly owing to inaccurate IBW in patients with skeletal height loss. We confirm that calculation of CD34 þ cell dose by IBW safely predicts engraftment for patients with haematological malignancies other than myeloma undergoing PBSC autograft.

Actual or ideal body weight to calculate CD34+ cell dose in patients undergoing autologous hematopoietic SCT for myeloma?

“…6 More importantly, although our initial publication assessed this relationship only for ANC 0.5 3 and Maclean et al's 6 for ANC 0.5 and plt 20, this series establishes the relationship for ANC 1.0 and plt 50 as well. Myeloma is the commonest indication for high-dose chemotherapy with autotransplantation now, and therefore addressing this question in this group of patients is relevant.…”

“…Cell dose based on IBW also correlates better with more clinically meaningful measures of outcome after allogeneic HSCT such as the risk of GVHD, TRM and disease-free survival. 2,5 Maclean et al 6 used the statistical techniques described by us 3 to confirm that the CD34 þ cell dose based on IBW correlated better with engraftment than that based on ABW, but felt that this relationship was inadequate in myeloma patients, possibly because of vertebral fractures and height loss-which underestimated IBW. On the basis of our work, 3 we have continued to use IBWbased calculations for all patients, including those with myeloma.…”

“…However, there are data suggesting that ideal body weight (IBW) may be a better basis for calculating cell dose, [1][2][3][4][5][6][7] and this is our standard practice. Cell dose based on IBW correlates better with engraftment after autologous 1,3,6 and allogeneic 4,7 HSCT. Cell dose based on IBW also correlates better with more clinically meaningful measures of outcome after allogeneic HSCT such as the risk of GVHD, TRM and disease-free survival.…”

Optimal mobilization method and CD34+ dose calculation for autologous PBSC transplant in myeloma patients: two important unresolved questions

“…Although it is virtually universal to express cell doses for hematopoietic SCT in terms of ABW, there are data suggesting that IBW may be a better basis for calculating cell dose. 16,17 This was studied further in 514 MM autografts in this study. IBW-based cell doses correlated slightly better with engraftment than ABW.…”

“…Lenalidomide originates myelosuppression and some authors have recommended the use of CY before growth factor to ensure collection, although this needs further research. 17 Other new drugs for MM should be evaluated regarding their influence on mobilization. On the other hand, some groups have observed best mobilization results with pegylated G-CSF (pegfilgrastim) compared with standard G-CSF not pegylated.…”