Risk of Post‐Transplant Malignancy After Isolated Heart Transplant Among Adult Patients With Congenital Heart Disease

INTRODUCTION: Patients with congenital heart disease (CHD) are at increased risk of cancer. In patients with CHD and advanced heart failure, isolated heart transplantation (HT) can be considered. In the overall HT population, immunosuppression after HT increases the risk of post-transplant malignancy (PTM). However, cancer outcomes among adult HT patients with CHD have not been investigated. METHODS: Patients aged ≥ 18 years who received HT between January 1, 2010 and December 31, 2021 were identified using the United Network for Organ Sharing (UNOS) registry. Patients with CHD were compared to those without. T primary outcome was a composite outcome of PTM or death due to malignancy. Multivariable Fine-Gray competing-risk regression was used to estimate the subhazard ratio (SHR) of primary and secondary outcomes. RESULTS: Of the total of 29717 patients with HT were included, 1017 (3.4%) had CHD. Patients with CHD were younger, more likely to be female, and have had prior cardiac surgery. After multivariable competing-risk regression, CHD was associated with a higher risk of the primary outcome (SHR 1.43, 95% CI 1.15-1.80). Among patients who developed PTM, the median time to diagnosis of first PTM (median 36 vs. 46 months, p = 0.027) was shorter in patients with CHD. Among patients with CHD, survival after PTM was significantly lower compared with patients without malignancy (HR 3.32, 95% CI 2.03-5.43). CONCLUSIONS: Among adult patients with HT, CHD was associated with an increased risk of PTM. Further investigation is warranted to identify risk factors and screening strategies for malignancy in this patient population.