Role of Chemotherapy before Allogeneic Stem Cell Transplantation (ALLO-SCT) from an HLA-Identical Sibling Donor for Myelodysplastic Syndrome (MDS).

The role of chemotherapy before allo-SCT remains unclear. We analyzed the data of 283 patients (median age 41 years, range 16–65 years) who underwent allo-SCT from an HLA-identical sibling donor for MDS that were reported to the Japan Society for Hematopoietic Cell Transplantation. One hundred eighty-eight patients had received chemotherapy before allo-SCT (Chemo group), whereas 95 had not (NoChemo group). The Chemo group included significantly higher proportion of patients with advanced disease and poor karyotype than the NoChemo group, (p<0.0001 and p=0.004, respectively). Overall survival (OS) at 5 and 10 years was 48.8% and 42.5%, respectively. Multivariate analyses identified karyotype, FAB classification, and the history of chemotherapy before allo-SCT as significant predictors for OS. The cumulative incidence (CI) of grade II–IV and III–IV acute GVHD among those who achieved engraftment was 33% and 10%, respectively. Chronic GVHD developed in 110 (53%) among 209 patients who survived more than 100 days. The CI of relapse in those who developed grade II–IV acute GVHD and those who did not was 39.6% and 19.5%, respectively (p=0.086). The CI of relapse in those who developed chronic GVHD and those who did not was 22.0% and 20.8%, respectively (p=0.82). Then, we analyzed only 139 patients with RAEBt or leukemic transformation (LT). Twenty-eight patients belong to the NoChemo group and 111 patients belong to the Chemo group. The proportion of patients with a poor karyotype was equivalent between the two groups (p=0.44). The duration from diagnosis to allo-SCT was shorter in the NoChemo group, with marginal significance (161 days vs. 248 days in median, p=0.07). The OS curves of the NoChemo group and CR patients in the Chemo group were superimposed (57% vs. 54%, p=0.81). The CI of relapse was 26.2% in the NoChemo group and 27.6% in CR patients in the Chemo group (p=0.83). Non-relapse mortality was also similar between the two groups (18.8% vs. 17.8%, p=0.86). In conclusion, this study confirmed that allo-SCT from an HLA-identical sibling donor offers the potential for long-term survival in patients with MDS. It seems that allo-SCT may be beneficial as primary treatment for patients with a low blast cell count or those with an advanced MDS but with an indolent course. GVHD did not appear to have a clear beneficial effect on the CI of relapse.