Minimal Identifiable Disease and the Role of Conditioning Intensity in Hematopoietic Cell Transplantation for Myelodysplastic Syndrome and Acute Myelogenous Leukemia Evolving from Myelodysplastic Syndrome
Festuccia, M.; Deeg, H.J.; Gooley, T.A.; Baker, K.; Wood, B.L.; Fang, M.; Sandmaier, B.M.; Scott, B.L.
Biology of Blood and Marrow Transplantation Journal of the American Society for Blood and Marrow Transplantation 22(7): 1227-1233
ISSN/ISBN: 1523-6536 PMID: 27064057 DOI: 10.1016/j.bbmt.2016.03.029
Allogeneic hematopoietic cell transplantation (HCT) is the only known treatment with curative potential for myelodysplastic syndrome, but relapse is a major cause of failure. We studied results in 289 patients transplanted between June 2004 and December 2013. Minimal identifiable disease (MID) markers pre-HCT were determined by multiparameter flow cytometry (MFC) and cytogenetics on marrow aspirates. The impact of MID on outcome after low- and high-intensity conditioning HCT was determined. Among 287 assessable patients, 68 (23.7%) had more than 5% marrow blasts at HCT; 219 patients were in morphologic remission but 154 (53.7%) were MID positive, whereas 65 (22.6%) were MID negative. The impact of MID on outcome was significantly different between patients who received low-intensity conditioning and patients who received a high-intensity regimen. The impact of conditioning intensity differed across the various MID categories. In particular, the risk of overall mortality was higher with low-intensity than with high-intensity regimens for patients who were positive for MID by cytogenetics regardless of positivity by MFC (HR, 1.67 if MFC positive/cytogenetics positive, HR, 7.23 if MFC negative/cytogenetics positive). On the other hand, patients who were MID negative by both MFC and cytogenetics had similar risks of mortality with low- and high-intensity regimens (HR, .99). The main factor responsible for mortality after low-intensity conditioning in MID-positive patients was relapse. The presence of MID should be considered when deciding on conditioning intensity because it identifies subgroups of patients who may benefit from high- or low-intensity conditioning.