Survival and late mortality among patients who survived disease-free for 2 years after stem cell transplantation

Abstract

Most events that limit life expectancy after allogeneic haematopoietic stem cell transplantation (allo-HSCT) occur within the first 2 years; however, treatment outcomes in long-term survivors who survive for at least 2 years post-HSCT without relapse are yet to be elucidated. To explore the life expectancy trends and late complications and to assess the main mortality-related factors, we investigated the characteristics of patients who received allo-HSCT for haematological malignancies from 2007 to 2019 in our centre and survived in remission for 2 years. A cohort of 831 patients was enrolled; of these, 508 received grafts from haploidentical-related donors (61.1%). The estimated overall survival rate at 10 years was 91.9% (95% confidence interval [CI], 89.8-93.5), which was affected by prior grade III-IV acute graft-versus-host disease (GVHD) (hazard ratio [HR], 2.98; 95% CI, 1.47-6.03; p = 0.002) and severe chronic GVHD (HR, 3.60; 95% CI, 1.93-6.71; p < 0.001). The probability of late relapse and non-relapse mortality at 10 years was 8.7% (95% CI, 6.9-10.8) and 3.6% (95% CI, 2.5-5.1) respectively. The top cause of late mortality was relapsed (49.0%). Projected long-term survival in 2-year disease-free survivors following allo-HSCT was excellent. Strategies should be implemented to minimise the late death-specific hazards in recipients.

Keywords: allogeneic haematopoietic stem cell transplantation; haematological malignancy; late mortality; long-term survival.