Is Not Age, But Comorbidities. Allogeneic Hematopoietic Stem Cell Transplantation In Patients Older Than 50 Years In Argentina

We retrospectively reviewed 137 medical records of patients older than 50 years receiving an allogeneic hematopoietic stem cell transplant (HSCT) in 9 centers from Argentina. We evaluated the following characteristics: sex, age, diagnosis, stage, comorbidities (according to the HCT-CI score), type of donor, histocompatibility, source, conditioning and immunosupression. We analyzed the incidence and severity of acute Graft-vs-Host disease (aGVHD) with Chi Square, Overall Survival (OS) and Disease Free Survival (DFS) with Kaplan Meier and Relapse, Non Relapse Mortality y chronic GVHD (cGVHD) with CI. For multivariate analysis (MA) we included variables that in univariate had a p<0.2, used Cox regression model for time dependant outcomes and logistic regression for dichotomic variables, considering significant a p<0.05.

Patients characteristics are listed in table 1. Between January 1997 and July 2013, 137 transplants were performed in adults older than 50 years, with a median follow up 1.3 years. Acute GVHD incidence was 41% (19% were grade II and 7.3% III-IV). The only variable associated with aGVH clinically significant (G II-IV) was AML that was protective (14% vs 35%, p<0.01; significant in MA, HR 0.29; 95% CI 0.12-0.72). Chronic GVHD incidence was 25%, extensive in 9.4% and the only risk factor for this outcome was MPN (1-3 years 40%-NA vs 12-20%, p=<0.01). Global OS 1 and 3 years was 44 and 20%, DFS was 33 and 20%, Relapse was 35 and 41% and NRM was 36 and 43% respectively. Co-morbid patients showed a significant increase in NRM (HCT.CI 0 vs 1 vs ≥2, 1-3 years 17-24%, 40-46% and 45-67%, p=0.01; significant in MA, for HCT.CI 0 vs ≥1, HR 2.4, 95% CI 1.12-5.25), as well as male patients (1-3 years 36-47% vs 23-27%, p=0.03), MPN (1-3 years 43-65% vs 29.34%, p=0.01) and Cyclosporine based immunosuppressant regimen (CSA) vs tacrolimus (1-3 years 47-53% vs 25-36%, p=0.01). AML patients experienced a higher relapse rate (1-3 years 50-50% vs 28-32%, p<0.01) as well as Fludarabine-Busulfan conditioning (1-3 years 45-48% vs 31-32%, p=0.02). Finally patients without comorbidities (HCT.CI 0 vs ≥1) had higher OS (1-3 years 54-30% vs 36-16%, p=0.03) and DFS (1-3 years 43-31% vs 30-15%, p=0.05) as well as tacrolimus vs CSA base regimen that had higher OS (1-3 years 49-25% vs 31-13%, p=0.01) and DFS (1-3 year 41-26% vs 20-11%, p<0.01; significant in MA, HR 0.56, 95% CI 0.33-0.98). Age (older than 60 vs younger), type of donor, use of myeloablative conditioning regimen and source did not showed any significant difference in the outcome analyzed.

HSCT is a valid therapeutic option for older patients. In this retrospective analysis of patients older than 50 years, we found that the main risk factors that impact in transplant outcome are patients comorbidities and not age, whereas transplant related toxicities increase with the number of comorbidities and therefore decrease OS and DFS. Beyond the fact that certain disease experienced more aGHVD (AML) or cGVHD and higher NRL (MPN) the other factor significantly related in transplant outcome was the use of tacrolimus vs CSA.

No relevant conflicts of interest to declare.