autologous blood and marrow transplantation - Blog Science ...

Boyer and Yeager 95
outcomes after UD BMT in patients with leukemias are inferior compared with
matched sibling BMT, with the only exception being patients who are not in
remission at the time of transplant, in which outcomes are similar (approximately
10-15% 3-year survival). 6
The inferior outcomes with UD BMT compared with
matched sibling BMT are due to the two- to threefold increase in transplant-related
mortality, which is up to 70% in high-risk patients. This makes it especially
important to examine the outcomes of UD BMT compared with autoBMT for ALL.
Two recent, large retrospective analyses have attempted to answer the clinical
question of whether to offer UD BMT vs. autoBMT for patients with high-risk
ALL. One report from the European Group for Blood and Marrow Transplantation
(EBMT) and International Marrow Unrelated Search and Transplant (IMUST)
groups found for ALL patients matched in age, stage, and year of transplant a 2year
DFS of 39 ± 5% for UD BMT vs. 32 ± 3% for autoBMT. 7
The other report
focused on 214 ALL patients treated with autoBMT at two centers compared with
337 ALL patients treated with UD BMT reported to the National Marrow Donor
Program (NMDP) in a similar time period, with the majority (68%) of patients =0.0001).
While these two studies help provide some guidance to the clinician, in reality
local selection bias probably plays a significant role in transplants done to date, and
will continue to play a role in the future. There are more centers that offer UD BMT
than autoBMT for ALL, due to the technology necessary to perform bone marrow
purging in autografts. This fact alone undoubtedly is a factor in selection bias. The
fact that unrelated donor searches and activation take 3 months or longer also make
for a complicated bias in that patients waiting for UD BMT may self-select and
become ineligible due to disease progression. However, it is also plausible that
patients are preselected for certain favorable characteristics when referred for
autoBMT. Without prospective and randomized studies, many unanswered
questions will remain. A crude comparison of the outcome and treatment-related
mortality for the different modalities discussed is outlined in Table 1.
MECHANISMS OF FAILURE OF ALLOBMT VS. AUTOBMT IN ALL
The causes of failure in autoBMT are overwhelmingly linked to leukemia
recurrence. What role is played by purging the bone marrow graft of residual