Prognostic Factors for Outcomes of Pediatric Patients with Refractory or Relapsed Acute Leukemia Undergoing Allogeneic Progenitor Cell Transplantation

Allogeneic stem cell transplantation (SCT) is the only curative therapy for patients with refractory or relapsed acute leukemia, although the prognosis remains poor. Few reports have described outcomes of SCT in pediatric patients with refractory acute leukemia. To identify prognostic factors for these patients, we retrospectively evaluated SCT outcomes for advanced acute leukemia in 82 pediatric patients from 3 transplant units in Nagoya City between 1990 and 2008. Median age at transplantation was 8 years (range, 0.5-17 years). Transplantation was performed in the first refractory relapse for 53 patients (64.6%), in the second or subsequent relapse for 16 patients (19.5%), and during primary induction failure for 13 patients (15.9%). Only 4 patients (4.9%) underwent transplantation in the untreated first relapse, and 39 patients (47.6%) received unrelated donor progenitor cells. Of the 82 patients, 61 died (77.9%), with a median survival of 7.1 months (95% confidence interval [CI], 4.2-10.0 months). Median disease-free survival (DFS) was 4.7 months (95% CI, 2.6-6.9 months). In multivariate analysis, peripheral blood blasts, cord blood transplantation, and more than 3 courses of previous salvage chemotherapy were predictive of DFS. These results support the notion that allogeneic SCT offers only a small chance of cure for most pediatric patients with refractory or relapsed acute leukemia, and suggest that reduction of the leukemia burden and earlier optimal timing of transplantation are essential for long-term survival even in patients with refractory acute leukemia.

Key Words: Allografting, Pediatric patients, Acute leukemia, Refractory or relapsed