Single-center analysis of relapse risk factors and prognosis in 256 cases of ETV6::RUNX1-positive pediatric acute lymphoblastic leukemia

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy, and although ETV6::RUNX1–positive B-cell ALL generally carries a favorable prognosis, it has a notable risk of late relapse. This study aimed to identify key relapse-associated risk factors and evaluate their impact on survival outcomes in children with ETV6::RUNX1–positive ALL. METHODS: We performed a retrospective cohort study including 256 pediatric patients diagnosed with ETV6::RUNX1–positive ALL at the Children’s Hospital of Soochow University between May 2008 and August 2020. Clinical characteristics, treatment responses, and relapse patterns were assessed. Independent predictors of relapse were identified using multivariate logistic regression, and survival outcomes were analyzed using the Kaplan–Meier method. RESULTS: Elevated initial white blood cell (WBC) count (≥ 50 × 10⁹/L), poor steroid response at day 7, and persistence of the ETV6::RUNX1 fusion transcript at the first post-therapy minimal residual disease assessment were significant independent predictors of relapse (P < 0.05). Among relapsed patients, early relapse (within 36 months of diagnosis) and lack of hematopoietic stem cell transplantation (HSCT) were associated with markedly inferior survival (5-year overall survival (OS): 17.6% vs. 55.6%, P = 0.006). CONCLUSIONS: This study identifies three critical risk factors for relapse in ETV6::RUNX1–positive pediatric ALL and highlights the adverse prognostic impact of early relapse. Importantly, the persistent detection of ETV6::RUNX1 fusion transcript at initial minimal residual disease (MRD) evaluation emerged as a novel and independent biomarker for early risk stratification. These findings may guide refinement of individualized therapeutic strategies to improve long-term outcomes in this pediatric subgroup.