Clinical characteristics and prognosis of 197 pediatric patients with refractory cytopenia: A single-center retrospective analysis

Abstract Refractory cytopenia of childhood (RCC) is a common subtype of pediatric MDS characterized by variable degrees of cytopenias, <5% blasts in the BM, <2% blasts in the PB and dysplastic changes in 2 or 3 lineages or exceeding 10% in one single lineage. Due to its similarities with aplastic anemia and its heterogeneity, the knowledge of management and outcome of RCC is limited. Our study retrospectively analysed 184 children between 2007 and 2022 with median follow-up of 89 months (range, 4 to 280), focusing on clinical and molecular features, treatment, evolution, and survival. The patients fulfilled the International Consensus Classification of Myeloid Neoplasms and Acute Leukemias of RCC. The median age at diagnosis was 7 years old (range, 1 to 16) and 56.5% of patients were female (n=104). At baseline, 64 patients were transfusion dependent, 120 patients were transfusion independent. Bone marrow evaluation showed 68.7% patients were hypocellular. In our corhort, 5 patients progressed to myeloid neoplasms. The cumulative incidence of myeloid neoplasms in 10 years was 4.2%. Patients with -7/7q- was significantly related to clonal evolution. In transfusion-dependent patients, IST therapies still showed some efficacy, with overall response rates of 66.7% for CyA, 76.2% for CyA plus androgen, and 66.7% for ATG, all of which were comparable to each other.And these regimens showed similar response rates to HSCT but the complete response rate of HSCT was significantly higher at 83.3%, compared to 38.6% for IST drugs (P = 0.046). Furthermore, for patients who failed IST, HSCT offered a substantial benefit, yielding both higher overall response and complete remission rates than continued drug therapy. In transfusion-independent patients, 19 patients (16.7%) in the watch-and-wait (WW) group maintained stable disease without further intervention, a proportion comparable to that of patients treated with drugs, including CyA, CyA plus androgen.However, in terms of hematologic improvement, drug therapy was significantly more effective than watch-and-wait. CyA treatment(48%) showed a tendency to higher response rate than CyA plus androgen(35.7%,P=0.081). In our corhort, 39 patients (34.2%) progressed to transfusion dependency. Dysplastic changes in megakaryocytes at baseline were found to be associated with a higher rate of progression(P=0.043). For these patients, hematopoietic stem cell transplantation (HSCT) showed a superior response rate (94.4%) compared to continued drug therapy. Our study presents the clinical characteristics of RCC and, through long-term follow-up, provides a detailed analysis of its disease progression and treatment outcomes. These findings emphasize the importance of personalized management strategies for RCC patients.