The conditional benefit of being alive and disease free at 2 years after transplant: a long term survival evaluation among 456 patients affected by acute myeloid leukemia.

Risk factors for relapse and non-relapse mortality (NRM) in the first years after allogeneic hematopoietic stem cells transplant (allo-HSCT) for acute myeloid leukemia (AML) are well known, but their correlation with long-term survivorship is unclear. This study aims to evaluate factors that impact on long-term survival after allo-HSCT in AML. We retrospectively analyzed data of 456 consecutive patients who received a first allo-HSCT in our center, regardless of conditioning intensity, GvHD prophylaxis, donor matching and HSC source. At transplant, two hundred and four patients (44%) were in CR1, 62 patients (14%) in CR>1, 27 (6%) in CR MRD+ and 163 patients (36%) in active disease (AD). Two-hundred and thirty-nine patients (52%) were alive 2 years after allo-HSCT. Median follow-up was 6.1 years. The 5 years OS was 63% for CR1, 38% for CR>1 and 25% for AD. However, in patients alive and disease free 2 years after allo-HSCT the probability of being alive for 3 more years was 86% for CR1, 72% for CR>1 and 79% for AD, with no statistically significant differences between CR>1 and AD. Other variables associated with better outcomes included younger age, more recent transplantation, and having a female donor for a male recipient. Relapse remained the main cause of death, even among long-term survivors. In conclusion, the negative impact of advanced disease at the time of allo-HSCT appears to progressively reduce after transplantation, highlighting the excellent long-term outcomes of patients who remain disease-free at 2 years after allo-HSCT, regardless of pre-transplantation disease status.