Autologous hematopoietic stem cell transplantation in adult acute lymphoblastic leukemia: still not out of fashion

The role of autologous hematopoietic stem cell transplantation (autoHSCT) in adult acute lymphoblastic leukemia (ALL) is still unclear. We retrospectively analyzed the results of the autoHSCT and maintenance therapy, with oral 6-mercaptopurine and methotrexate, in comparison to conventional-dose chemotherapy in the consolidation treatment of adult ALL and lymphoblastic lymphoma (LBL). The patients, with HLA identical sibling donor, underwent allogeneic transplantation, while the others were treated with autoHSCT and maintenance therapy with oral 6-mercaptopurine and methotrexate, or by conventional-dose chemotherapy (patient's decision, no autologous hematopoietic stem cells harvest). Sixty consecutive adult patients (median age 35.2 years; range 17.3 to 70.7) with ALL (n = 52), LBL (n = 7), and acute biphenotypic leukemia (n = 1) were treated in our center from 1997 to 2007. Patients treated with chemotherapy alone (n = 35) had a shorter median progression-free survival (PFS) compared to patients who underwent autoHSCT plus maintenance therapy (n = 18), 8.4 and 46.8 months, respectively (p = 0.017). Patients treated with chemotherapy alone had also a shorter median overall survival (OS) compared to patients treated with autoHSCT: 13.0 vs. 46.8 months (p = 0.046). The differences remained statistically significant even after excluding patients with Ph positivity. We can conclude that, in our case, autoHSCT followed by maintenance chemotherapy is a good option for adult patients with ALL and, in standard-risk and high-risk patients, provides more favorable OS and PFS rates compared to patients treated by chemotherapy alone. However, we are aware of the fact that our analysis may have been distorted by the fact that the analysis is retrospective, that treatment with autoHSCT was based on patient's decision, and that chemotherapy may have been administered to negatively selected patients.