Congenital heart disease and the risk of cancer: The importance of understanding associated comorbidities

Congenital heart disease (CHD) is the most common birth defect affecting nearly 9 per 1000 live births. 1 Survival for patients with CHD has dramatically increased over the last several decades with nearly 97% of patients expected to reach adulthood.2 With this rise in life expectancy, there has been a parallel rise in the need to understand the burden of acquired diseases in this patient population.This knowledge is critical for the assessment of contributing factors to morbidity and mortality, identification of modifiable risk factors and the implementation of CHD specific care guidelines aimed at addressing this complex array of comorbidities.Prior work has demonstrated an association between CHD and cancer.3 The present study published in the The Lancet Regional Health-Europe by Karazisi et al expands this understanding by evaluating the risk of cancer from birth to adulthood.4 Leveraging the broad and longitudinal nature of the Swedish Health Registry, the authors identified 89,000 patients with CHD and compared them to age and sex matched controls.They found that the risk of cancer in CHD was 23% higher as compared to the control group (HR 1¢23, 95% CI 1¢19-1¢27).Interestingly, this risk remains elevated (HR 1¢18, 95% CI 1¢14-1¢22) even when accounting for genetic syndromes and organ transplantation.The risk was highest among younger patients (0-17 years of age, HR 3¢2, 95% CI 2.¢9-3¢56) and those born in later cohorts (1990-2017, HR 2¢88 [95% CI 2¢57-3¢22]).Malignancies of the skin had the highest incident rate ratio among the whole CHD population as compared to controls; but among the youngest age group (0-17 years) the most common cancer diagnosis were those of primary lymphoid and hematopoietic origin.While congenital heart surgery did not increase the risk of cancer overall, there was an increase in risk amongst children who had CHD surgery at less than 1 year of age.