Other Issues In Transplantation For All Stem cell source and preparative regimen

There is no preparative regimen that yields superior results when used prior to transplant for ALL. Many centers employ regimens that include etoposide; however, this agent has not been shown to improve transplant outcomes among adults. The IBMTR has analyzed the outcomes in 298 patients who received HLA-matched sibling transplants for ALL in first or second remission. Long-term survival was superior in patients who received > 13 Gy of TBI, but no differences were noted when cyclophosphamide and etopo-side use were compared.49 Regarding stem cell source, no randomized trial has directly compared PBSC with bone marrow for ALL transplantation because of the rarity of this disease and large sample size that a clinical trial would need to demonstrate differences. While superior disease-free survival has been demonstrated with PBSC transplantation over stem cell transplantation using HLA-identical sibling donors, particularly with advanced malignancies, subgroup analyses in ALL are too small to demonstrate differences.50 A single retrospective analysis of 102 ALL patients who received an unrelated stem cell transplant demonstrated inferior survival among PBSC patients despite no differences in grade II-IV acute GVHD or chronic GVHD incidence.51 In this study, PBSC patients were less likely to receive TBI as conditioning (p = 0.06), which may have influenced outcome.49 Although used infrequently, umbilical cord transplantation has been attempted in adults with advanced ALL. The advantage of cord blood transplantation is the rapid access to stem cells and the potential for less GVHD than with other unrelated stem cell products. Too few transplants for ALL have been performed to make conclusive comments on the role of cord blood transplanta tion; however, the relative lack of GVHD could be associated with a high risk of relapse.

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