Treatment of children with acute myeloid leukaemia who relapsed after allogeneic haematopoietic stem cell transplantation.

Despite improvements in diagnosis and treatment, 30-40% of children with acute myeloid leukaemia (AML) experience relapse. For those who relapse after allogeneic haematopoietic stem cell transplantation (allo-HSCT), the prognosis is particularly poor, with limited reported literature on these patients. We reviewed the clinical course of 49 children with AML (28 males, 21 females) who received allo-HSCT between 1993 and 2011, and who had subsequently relapsed. Study endpoints included (i) complete remission (CR) rate after intensive chemotherapy, and prognostic factors for CR, (ii) disease-free survival (DFS) and overall survival (OS) for patients who achieved CR and (iii) OS for recipients of intensive chemotherapy and prognostic factors for OS. Of the 36 patients who received intensive chemotherapy after post-HSCT relapse, 26 (72%) achieved CR. For patients who achieved CR, 5-year DFS and OS were 32·6 ± 10·2% and 44·4 ± 11·1%, respectively. For all recipients of intensive chemotherapy, 5-year OS was 31·6 ± 8·7%. Cumulative incidence of treatment-related death was 14·4%. All three recipients of second HSCT died. Amongst prognostic factors predicting improved survival, only disease status at HSCT (early first CR vs. others) proved significant in multivariate study (Hazard Ratio 2·42, 95% Confidence Interval 1·02-5·74, P = 0·045). Treatment with curative intent was able to salvage a minor but important subset of children with AML who relapsed post-allogeneic transplant.