Optimizing diagnostic methods and stem cell transplantation outcomes in pediatric bone marrow failure: a 50-year single center experience

Abstract

Peripheral blood cytopenia, a frequent presenting symptom in pediatric patients, can be caused by bone marrow failure (BMF). Timely identification of patients with non-reversible BMF is of crucial importance to reduce the risks of invasive infections and bleeding complications. Most pediatric patients with severe persistent cytopenia, independent of the underlying cause, are offered allogeneic hematopoietic stem cell transplantation (HSCT) as curative therapy. Here we report on our management guidelines and HSCT outcomes of pediatric BMF patients to pinpoint improvements and future challenges. We formulated recommendations based on this 50 years' experience, which were implemented at our center in 2017. By analysis of the HSCT cohort of 2017-2023, the 5-year outcome data is presented and compared to historical outcome data. In addition, outcomes of patients transplanted for identified inherited bone marrow failure syndromes (IBMFS) are compared to severe aplastic anemia (SAA) outcomes to underline the often multiorgan disease in IBMFS with implications for long-term survival. Survival of pediatric patients with irreversible BMF has improved tremendously. SAA patients transplanted after 2017 had a superior 5-year overall (OS) and event-free survival (EFS) of 97% and 85% compared to 68% and 59% in the cohort transplanted before 2017 (p = 0.0011 and p = 0.017). A similar trend was seen for BMF, with an OS and EFS of 89% for those transplanted after 2017 compared to 62% and 59% (p > 0.05). This improvement is mainly related to better survival in the first months after HSCT. The long-term survival after HSCT is lower in IBMFS patients as compared to SAA patients due to secondary malignancies and multiorgan toxicity. Conclusion: Unbiased protocolized in-depth diagnostic strategies are crucial to increase the frequency of identifiable causes within the heterogeneous group of pediatric BMF. A comprehensive approach to identify the cause of BMF can prevent treatment delay and be useful to tailor treatment and follow-up protocols. What is Known: • Irreversible BMF in pediatric patients can be caused by a wide spectrum of underlying diseases including (pre)malignant disease, IBMFS and AA. Identifying the exact underlying cause of BMF is crucial for tailored therapy, however often challenging and time-consuming. • Frontline allogeneic HSCT is offered to most pediatric patients with severe BMF as curative treatment. What is New: • Protocolized unbiased diagnostics, short time to treatment (< 3 months) and maximal supportive care until curative treatment can prevent complications with a negative effect on survival such as infection and bleeding. • Personalized follow-up protocols for IBMFS patients are essential to prevent a second decline in survival due to long-term treatment toxicity and extra-hematological disease complications.

Keywords: Aplastic anemia; Bone marrow failure; Cytopenia; Hematopoietic stem cell transplantation; Immune suppressive therapy; Molecular analysis.

Fig. 1

Visual dictionary of the key elements involved in pediatric bone marrow failure and allogeneic hematopoietic stem cell transplantation. BMF; bone marrow failure, IBMFS; inherited bone marrow failure syndromes, HSCs; hematopoietic stem cells, SAA; severe aplastic anemia, IRD; identical related donor, GVHD; graft versus host disease, HSCT; hematopoietic stem cell transplantation

Fig. 2

Study flow diagram. In total, 228 pediatric patients with bone marrow failure were included. HSCT; hematological stem cell transplantation, BMF; bone marrow failure, SAA; severe aplastic anemia, CAMT; Congenital amegakaryocytic thrombocytopenia, CDA; congenital dyserythopoietic anemia, DBA; Diamond-Blackfan anemia, DC; Dyskeratosis congenita, FA; Fanconi anemia, MDS-RCC; Myelodysplastic syndrome-refractory cytopenia of childhood, SCN; sever congenital neutropenia, SDS; Shwachman-Diamond syndrome

Fig. 3

Survival outcomes. A, B SAA patients transplanted after 2017 have a significant higher 5-year OS and EFS. C, D Although not significant, a similar trend was observed indicating an improved survival for BMF patients transplanted after 2017. E, F 10 to 20 years post HSCT, a second decline in survival can be observed for BMF patients, which is not apparent for SAA patients. G, H For all donor types, treatment has been improved resulting in better survival outcomes after 2017. BMF; bone marrow failure, SAA; severe aplastic anemia