Background:
With increasing life expectancy of adults with congenital heart disease (ACHD), non-cardiac comorbidities, including malignancies, have become increasingly relevant. International studies suggest an elevated cancer risk and earlier tumor onset in this population; however, data on tumor characteristics and age at diagnosis in German ACHD cohorts remain limited. This study aimed to characterize tumor entities, age at cancer diagnosis, and potential associations with congenital heart disease severity and therapeutic exposure in a German ACHD cohort.
Methods:
A retrospective cohort analysis was conducted using data from the National Register for Congenital Heart Defects (NRAHF). Adults with congenital heart disease and a documented malignant disease were included. Clinical variables included age at cancer diagnosis, tumor entity, congenital heart defect complexity, and history of invasive cardiac therapies. Descriptive analyses were performed to characterize tumor distribution and age patterns. Subgroup analyses were conducted to assess potential associations between cardiac complexity, genetic factors, and age at cancer diagnosis. Sensitivity analyses excluding syndromic patients were performed to evaluate the robustness of findings.
Results:
A total of 97 patients with congenital heart disease and malignant disease were included in the analysis. The median age at cancer diagnosis was 35 years, with 65.2% of malignancies diagnosed before the age of 45 years. Early tumor manifestation remained evident after exclusion of syndromic patients, with a median age of 38 years at diagnosis. Breast cancer was the most frequent tumor entity (22.7%), followed by central nervous system (CNS) tumors (13.4%) and colorectal cancers (10.3%). The comparatively high proportion of CNS tumors represents a notable deviation from population-based cancer distributions. Furthermore, a substantial proportion of screening-relevant malignancies occurred before the recommended screening age. Of 38 evaluable screening-related tumors, 21 cases (55.3%) were diagnosed below the recommended screening threshold. This was particularly evident for breast cancer, with 73.9% of cases diagnosed before the standard screening age of 50 years (median age at diagnosis: 39.5 years). No statistically significant association was observed between congenital heart disease complexity and age at cancer diagnosis, although descriptive trends suggested younger onset in patients with more complex defects.
Conclusions:
This study demonstrates a markedly early onset of malignancies in adults with congenital heart disease and identifies a characteristic tumor distribution, including a notable proportion of CNS tumors and early-onset screening-related malignancies. The high frequency of tumors diagnosed below established screening ages highlights the potential need for risk-adapted cancer surveillance strategies in selected ACHD populations. Further large-scale prospective studies are required to confirm these findings and to evaluate implications for individualized cancer screening protocols in this growing patient population.
