Allogeneic Stem Cell Transplantation (allo-SCT) in 192 Acute Myeloid Leukemias (AML): A Single Center Experience From 1982 to 2010
Authors: Montes-Gaisan Carmen , Monge Jorge , Martin Clara , Diez Zurie , Hinostroza Johny Alberto , Nuez Javier , Albajar Marta , Richard Carlos , Conde Eulogio , Iriondo Arturo 
Published: October 2019

Abstract
Abstract 4498

Background:
Giving the fact that allo- SCT currently offers patients with high risk AML the best chance of cure, we`ve aimed to investigate the outcome of AML patients who have undergone allo-SCT in our center, considered as one of spanish reference hospital in SCT, and the parameters that have been able to influence in relapse rate (RR), overall survival (OS) and relapse free survival (RFS).

Methods:
Retrospective study in 192 AML patients who have undergone allo-SCT between 1982 and 2010. The analysis has been performed in 171 patients (85 male and 86 female) by excluding 21 acute promyelocitic leukemias (APL): 65 patients until 1999 and 106 since 2000. Median age was 37 1874 and median lecocyte count, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(13400/\hbox{ L }\frac{470}{250000}\) \end{document}. 82 were de novo AML and 87 were in morfologic complete remission (70 in first CR). 14 patients had received a previous SCT. Cytogenetic risk was as follows: 55 intermediate, 34 high and 11 low. Conditioning regimen was ablative in 162 patients: CyTBI (36), BuCy (31), BuFlu (30) and others (3). 130 patients (76) underwent a related allo-SCT (95 of them were matched) and 41 patients (24), an unrelated allo-SCT (64 of them were matched). Stem cell source was bone marrow (BM) in 146 patients (85) and only 3 patients received umbilical cord (UC). Graft versus host disease (GvHD) prophilaxis was based on Ciclosporine in 150 patients (88). Median time from last treatment was 73 days 12268.

Results:
The median follow-up of this study was 61 months 1317. OS at 1, 3 and 5 years were 57, 44 and 40. RFS at 1, 3 and 5 years were 62, 50 and 45. Early mortality (before day 100) was 26 (43 until 1999 and 15 since 2000, p0,0001): 18 patients because of infections, 10 because of toxicity, 9 because of disease and 7 because of EICH. Late mortality was 27 (more than the half because of relapse, with no significant difference between 19881999 and 20002010). Cumulative relapse incidence at 5 years was 35, with a median time of relapse of 4 months. Secondary malignancies incidence was 5. Multivariable analysis showed that Transplantation Related Mortality (TRM) was influenced by: year of allo-SCT (OS at 5 years of 49 if 20002010 vs 28 if 19821999, p0,0001), late engraftment (p0,002) and severe acute GvHD (OS at 5 years of 45 if no evidence/grade I-II vs 25 if grade III-IV, p0,071). The other important parameters which lost its univariable analysis significance were donor type, recipient age and conditioning regimen. No difference was found in case of HLA and ABO discordance or donor/recipient CMV status. Multivariable analysis also showed that RR and RFS at 5 years was influenced by: disease status at allo-SCT (50 if 1CR vs 0 if 2CR/PR/refractory disease, p0,002), chronic GvHD (67 if present vs 41 if absent, p0,035) and leucocyte count at diagnosis (54 if 20000/ L vs 37 if 20000/ L, p0,038). The other important parameters which lost its univariable analysis significance were cytogenetic risk, initial induction response and positive minimal residual disease (MRD) before allo-SCT. No diference was found in case of ethiologic classification or stem cell source.

Conclusions:
Allo-SCT is a curative procedure in AML patients (global RFS of 50 at 3 years), specially when disease is under control and patient develops chronic GvHD. In the last decade, there have been important improvements in the procedure which have led to a significant decrease in TRM, and consequently, a significant increase in OS.

Disclosures:
No relevant conflicts of interest to declare.