Current status of allogeneic HST for chronic myelomonocytic leukemia

Allogeneic hematopoietic SCT (HST) offers the only curative potential for patients with chronic myelomonocytic leukemia (CMML). However, there is a paucity of data addressing this approach in CMML. The disease is a relatively under-represented myelodysplastic (MDS)/myeloproliferative subtype among transplant eligible patients. Non-randomized studies suggest that long-term remissions are achievable when using myeloablative or reduced intensity conditioning transplantation. Allogeneic SCT for CMML is often reported as part of MDS registry data. The largest series in adult patients reported a disappointing long-term relapse-free survival (RFS) of 18%. The Fred Hutchinson Cancer and Research Center group reported a 40% long-term RFS for a mixed group of adults and children with CMML who were transplanted over two decades. In this study, we performed a literature search and reviewed available data for adult CMML patients undergoing HST. The dearth of data that span two decades with changing transplant practices prohibited us from performing a formal meta-analysis. However, we elected to present the current status of HST in adult CMML patients. Carefully selected CMML patients may have the most benefit from this curative approach.