Allogeneic hematopoietic stem cell transplantation in adolescent and adult patients with high-risk T cell acute lymphoblastic leukemia.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is often recommended for patients with T cell acute lymphoblastic leukemia (T-ALL) in second or later complete remission (≥CR2) and sometimes in high-risk (HR) patients in first complete remission (CR1). Between January 1995 and July 2009, 53 patients with HR T-ALL underwent allo-SCT at our institution. Median age was 18 years (range, 14-51). Thirty-two patients (60.3%) were in CR1, 18 (34%) were in ≥CR2, and 3 (5.7%) were in relapse. The cumulative incidence of nonrelapse mortality at 5 years was 22.5%. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 40.2%, and that of chronic GVHD was 43.7%. The majority of relapses (88.9%) occurred within 1 year after SCT. The cumulative incidence of relapse (CIR) at 5 years was 35.6%. CIR was 29.8% in patients in CR1, 35.3% in patients in ≥CR2 and all patients transplanted in relapse had disease recurrence post-allo-SCT (P = .000). Overall survival (OS) and disease-free survival (DFS) at 5 years were 43.5% and 41.8%, respectively. The 5-year OS was 53.5% (95% CI 34.5%-72.5%) and 5-year DFS was 52% (95% CI 33%-71%) in patients who underwent allo-SCT in CR1, compared with 31.9% (95% CI, 9%-54.8%) and 29.4% (95% CI 7.6%-51.2%) in those who underwent allo-SCT in ≥CR2. On multivariate analysis, disease status at SCT remained significantly associated with OS (P = .007), DFS (P = .002), and CIR (P = .000). The presence of extramedullary disease at diagnosis had no effect on the different outcomes. Grade II-IV acute GVHD was significantly associated with a lower OS (P = .006) and DFS (P = .01). Our data indicate that allo-SCT represents an effective treatment for HR T-ALL, particularly when performed in CR1.