Cumulative burden of subsequent neoplasms, cardiovascular and respiratory morbidity in young people surviving cancer

Background: Long-term childhood and young adult cancer survivors are at increased risk of the late effects of multiple chronic conditions. In this study we estimate the cumulative burden of subsequent malignant neoplasms (SMN), cardiovascular and respiratory hospitalisations in long-term survivors of childhood and young adult cancers and associated treatment risks. Methods: Five-year survivors of cancer diagnosed aged 0-29 years between 1992-2009 in Yorkshire, UK were included. The cumulative count of all hospital admissions (including readmissions) for cardiovascular and respiratory conditions and all SMNs diagnosed up to 2015 was calculated, with death as a competing risk. Associations between treatment exposures and cumulative burden were investigated using multiple-failure time survival models. Results: A total of 3464 5-year survivors were included with a median follow-up of 8.2 years (IQR 4-13 years). Ten-years post diagnosis, the cumulative incidence for a respiratory admission was 6.0 % (95 %CI 5.2-6.9), a cardiovascular admission was 2.0 % (95 %CI 1.5-2.5), and SMN was 1.0 % (95 % CI 0.7-1.4) with an average of 13 events per 100 survivors observed (95 %CI 11-15). The risk of experiencing multiple events was higher for those treated with chemotherapy drugs with known lung toxicity (HR = 1.35, 95 %CI 1.09-1.68). Discussion: Survivors of childhood and young adult cancer experience a high burden of morbidity due to respiratory, cardiovascular diseases and SMNs up to 20-years post-diagnosis. Statistical methods that capture multiple morbidities and recurrent events are important when quantifying the burden of late effects in young cancer survivors.