Clinical characteristics and long-term treatment outcomes in childhood myelodysplastic neoplasm: a nationwide population-based study in Korea.

BACKGROUND

Childhood myelodysplastic neoplasm (cMDS) is a rare condition with distinct biological and clinical characteristics. To characterize the epidemiological features of cMDS, including incidence, demographics, and underlying etiologies. We also aimed to identify prognostic factors and assess long-term outcomes associated with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with cMDS.

METHODS

This nationwide Korean study analyzed 484 patients < 19 years of age diagnosed with cMDS between 2003 and 2021, using data from the Korean National Health Insurance Service database.

RESULTS

Annual incidence ranged from 1.7 to 4.3 per million children, with 7.2% had a prior history of malignancy. A total of 180 patients underwent allo-HSCT for cMDS. The 5-year overall survival (OS) rates were 76.6% in the transplant group and 80.5% in the non-transplant group. Among non-transplanted patients, key prognostic factors included later period of diagnosis (hazard ratio [HR] 0.372, P = 0.012), history of prior malignancy (HR 3.329, P = 0.002), and chemotherapy for cMDS (HR 3.701, P = 0.002). Only CBT was significantly associated with increased mortality in univariate analysis of the transplant group (HR, 3.911; P = 0.008). The 10-year cumulative incidence of leukemia was 20.5%, with a significantly higher rate in the cMDS with increased blasts (cMDS-IB) group (53.3% vs. 19.4%, P = 0.002).

CONCLUSIONS

While many patients achieved stable disease control without allo-HSCT, monitoring remains essential due to the risk of leukemic transformation, particularly in therapy-related and cMDS-IB subtypes.