Role of Intensive Conditioning Regimens Followed by Allogeneic Stem Cell Transplantation in Patients with Acute Lymphoblastic Leukemia: A Long-Term Follow-Up.

Purpose: Acute lymphoblastic leukemia (ALL) remains a difficult disease to treat in adults and less than 40% of ALL patients could be alive at 5 years post-diagnosis. We investigated whether intensive conditioning regimens improve outcome of patients with ALL.

Methods: Retrospectively, we analyzed 24 patients (median age; 29 years) with ALL who underwent allogeneic transplantation in our institute between February 1991 and October 2003. The median follow-up time was 7.7 years. Sixteen patients were in first complete remission (CR1) and five patients were in second CR (CR2) and three patients did not attain CR (non-CR) at the time of transplantation. Five patients with Philadelphia (Ph) chromosome-positive ALL were included. Preparative regimens were cyclophosphamide (CY), total body irradiation (TBI) and etoposide based regimen (n=23) or CY, TBI, and cytosine arabinoside (n=1) followed by marrow (n=21) or peripheral blood (n=3) transplant from unrelated (n=7) or related donors (n=17).

Results: The 8-year overall survival (OS) rate and the 8-year disease-free survival rate for all cases were 48% and 39%, respectively. The 8-year OS of Ph negative and positive patients were 56% and 20%. The 8-year OS of CR1, CR2 and non-CR patients were 50%, 60% and 0%, respectively. Overall probability of the 8-year relapse rate was 47%. Treatment related mortality was 25%.

Conclusion: These results suggest that CY/TBI based intensive regimens are feasible for ALL patients and may be effective for Ph negative ALL patients in not only CR1 but also CR2.