This study aims to determine whether congenital heart disease increases chronic health risks and mortality in childhood hematological tumor survivors, explore potential shared genetic factors between these conditions, identify other factors affecting long-term outcomes and quality of life, and validate any discovered genetic links through mechanistic investigations.

Children with congenital heart disease have a significantly higher risk of developing hematological tumors compared to the general pediatric population, although the clinical characteristics and prognosis of such comorbid cases have previously lacked systematic investigation. The study is set to include children with comorbid congenital heart disease and hematological tumors, comparing them with those without congenital heart disease, to conduct a detailed analysis of their clinical data, treatment responses, and survival outcomes.

Inclusion Criteria:

1. Children with hematologic malignancies diagnosed by pathology or bone marrow aspiration/biopsy at member hospitals of the Hematologic Oncology Specialty Alliance between 2010 and 2025;
2. Aged 0-17 years at diagnosis, regardless of gender;
3. Completed standard treatment for hematologic malignancies and confirmed diagnosis of congenital heart disease by cardiac ultrasound and clinical evaluation;
4. Written informed consent can be provided by the child or their legal guardian.

Exclusion Criteria:

1. Presence of birth defects other than congenital heart disease;
2. Other serious cardiac conditions, malignancies, or comorbidities that may interfere with study results;
3. Inability to provide the information and data required for the study.

The study population will comprise pediatric patients with hematological malignancies who also have congenital heart disease, identified through a multi-center collaborative network spanning major tertiary hospitals across China. This cohort will include children aged 0-18 years at diagnosis who were treated between 2010 and 2025, with detailed clinical data collected retrospectively from participating medical institutions. The selection specifically focuses on patients who completed standard oncologic treatment and received confirmed congenital heart disease diagnoses through comprehensive cardiac evaluation.