BU- vs TBI-based conditioning for adult patients with ALL

Evidence suggests an advantage for TBI over BU as a component of conditioning regimens for allogeneic hematopoietic cell transplant in patients with ALL. We have employed both TBI and BU for conditioning in ALL and reviewed our experience to compare outcomes. From July 1989 to June 2008, we identified 86-adult ALL patients treated with either a TBI- or BU-based regimen and transplanted with either a well-matched sibling or unrelated donor. Data including demographics, immunophenotype, disease status and cytogenetic risk were examined by Cox proportional hazards analysis. Patients treated with TBI were older (median age 40 vs 33 years; P=0.018), had a higher-risk cytogenetic profile (P=0.010), were more often transplanted using an unrelated donor (P=0.038) and were treated more recently (P<0.001). There was a significant improvement in EFS (P=0.046), and a trend to improved OS (P=0.08) in patients treated with TBI compared with those treated with BU. However, the advantage for TBI could not be confirmed by multivariable analysis where only disease status retained statistical significance.