Survival Outcome and Long-Term Follow-up of Autologous and Allogeneic Stem Cell Transplantation (SCT) in Acute Myeloid Leukemia (AML): A 30 Years Single-Center Experience
Authors: Montes-Gaisán Carmen , Perez German , Bermudez Arancha , Cuesta Amalia , Richard Carlos , Conde Eulogio 
Published: October 2019

Abstract
Background:
Post-remission treatment for AML is very aggressive and many times a SCT is needed. Comparisons between Allo-SCT and Auto-SCT ve always shown more Transplant Related Mortality (TRM) but less Cumulative Incidence of Relapse (CIR) in the first group. Our study describes, not only the long-term survival outcomes, but also the quality of life in long survivors.
Methods:
Retrospective study of 274 patients diagnosed with non-promyelocytic AML who underwent SCT between 1982 and 2011 in our center. Characteristics in the 162 Allo-SCT and the 112 Auto-SCT groups of patients were respectively: median age of 38 and 45 years old, secondary AML in 20% and 10%, refractory to Induction AML in 16% and 3%, pre-SCT status different from Complete Remission (CR) in 13% and 3% and year of SCT before 2005 in 53% and 86%. No significant differences between both groups were found in other risk factors as hyperleucocytosis at diagnosis or adverse cytogenetics.
Results:
With a median follow-up of 55 months [2-316], Overall Survival (OS) until 1997 in Allo-SCT and Auto-SCT were respectively, 40% and 61% at 1 year and 28% and 45% at 5 years (figure 1), but from 1997, 66% and 70% at 1 year and 47% and 48% at 5 years (figure 2). Disease Free Survival (DFS) until 1997 in Allo-SCT and Auto-SCT were respectively, 50% and 65% at 1 year and 38% and 46% at 5 years, but from 1997, 67% and 63% at 1 year and 52% and 47% at 5 years. In the last 15 years, no differences were found between both groups in OS nor DFS. CIR in Allo-SCT and Auto-SCT were respectively, 18% and 32% at 1 year and 24% and 50% at 5 years, without dependence on year of SCT. No relapse was observed later in any group. TRM until 1997 in Allo-SCT and Auto-SCT were respectively, 30% and 7% at 1 year and 35% and 9% at 5 years, but from 1997, 16% and 2% at 1 year and 25% and 4% at 5 years. Multivariable analysis showed that the only risk factor with a negative impact on OS was not having achieved CR at the time of SCT. Other variables as older age, hyperleucocytosis at diagnosis, adverse cytogenetics, secondary AML or sooner year of SCT lost their univariable analysis significance.
Allo-SCT: From the 162 patients, 72(44%) are alive by this moment, 43(60%) with ECOG 0, 21(29%) with ECOG 1 and the other 8(11%) with ECOG 2, basically because of graft versus host disease (GVHD in 39 patients, 21 steroid-dependent and 3 refractory to any treatment). All of them have been in CR during the last 2 years of follow-up. In contrast, 90(56%) patients have died: 52(58%) because of SCT complications (20 infections, 16 GVHD, 8 toxicity and 8 mixed causes), 33(37%) because of disease and 5(5%) because of other causes. With a median follow-up of 43 months [2-316], there have been 4 secondary neoplasm, all of them solid ones, which appeared with a median of 242 months [179-311] from SCT. None of them had previously received radiotherapy.
Auto-SCT: From the 112 patients, 43(38%) are alive by this moment, 32(74%) with ECOG 0 and the other 11(26%) with ECOG 1. All of them have been in CR during the last 2 years of follow-up. In contrast, 69(62%) patients have died: 45(65%) because of disease, 14(20%) because of SCT complications and 10(15%) because of other causes. With a median follow-up of 93 months [5-230], there have been 6 secondary neoplasm, 5 of them hematologic ones, which appeared with a median of 90 months [76-115] from SCT. None of them had received radiotherapy, but previously treated hematopoietic stem cells. Only one is alive at the time of last follow-up.
Conclusions:
In one hand, despite the high incidence of relapse in Auto-SCT in any period, OS is lower in Allo-SCT during the first years [1982-1996], although it has a tendency towards OS in Auto-SCT from 1997 because of the decrease in TRM, which is more significative in Allo-SCT. In the other hand, DFS is slightly higher in Allo-SCT during the last years [1997-2011], although the quality of life in long survivors is worse, basically because of GVHD.
In summary, we have not really found differences between Allo-SCT and Auto-SCT in terms of OS and DFS in our series, so both procedures are efficient to treat AML (near 50% of the patients in both groups are alive at 5 years from SCT in recent years). The decrease in TRM until 4% at 5 years in Auto-SCT makes it a good choice, particularly for older patients without risk factors. However, the development of secondary hematologic neoplasms is a relevant fact, with an incidence of 11% and a high late mortality.
Figure 1 Figure 1.
Figure 2 Figure 2.

Disclosures
No relevant conflicts of interest to declare.