Kaplan-Meier estimates of disease-free survival for recipients of UCBT with Bu/Flu/TBI and Cy/Flu/TBI conditioning. Overall, 5 Bu/Flu/TBI and 11 Cy/Flu/TBI recipients were alive and disease-free at 1 year after transplantation, giving a probability of disease-free survival of 24% (95% CI, 6%-42%) and 41% (95% CI, 15%-76%) at 1 year, respectively. The differences between the 2 regimens were not significant (P = .15).