Paediatric, adolescent and young adult survivors of Hodgkin’s lymphoma are at substantially higher risk of cardiovascular disease compared to matched community controls due to curative treatments, according to an analysis appeared in the journal Lancet Oncology.

In particular, long-term survivors of childhood Hodgkin’s lymphoma who received high doses of radiotherapy have an increased risk of grade 3 to 5 cardiovascular events.

Nickhill Bhakta, and colleagues performed an analysis of data from survivors of Hodgkin’s lymphoma participating in two ongoing studies of the St Jude Children’s research Hospital, the St Jude Lifetime Cohort Study (SJLIFE), and the St Jude Long-term Follow-up Study (SJLTFU). The SJLIFE cohort study was begun on 27 April 2007 to allow longitudinal clinical evaluation of health outcomes of survivors of childhood cancer treated or followed at St Jude Children’s Research Hospital, and SJLTFU is an ongoing administrative system-based study initiated in 2000 to collect outcome and late toxicity data for all patients treated at the hospital for childhood cancer.

The cohort in this analysis included patients treated at St Jude Children’s Research Hospital who reached 18 years of age and were at least 10 years post-diagnosis of pathologically confirmed primary Hodgkin’s lymphoma. The analysis aimed to determine the incidence of cardiovascular morbidity in paediatric, adolescent, and young adult survivors of Hodgkin’s lymphoma, which was currently unknown.

The investigators applied the cumulative burden metric to a comparison of the occurrence of cardiovascular events using confirmed medical data from the survivors of Hodgkin lymphoma in both studies. The comparison of outcomes was made between a sample of SJLIFE cancer survivors and frequency-matched subjects in the community, who served as controls and were aged 18 years or older at the time of assessment. Survivors and controls were stratified into 5-year age blocks within each sex.

Although community controls were selected irrespective of previous medical history, first-degree relatives of patients of the St Jude Children’s Research Hospital, individuals with a history of childhood cancer, and pregnant women were excluded from the community control population.

All survivors in the SJLIFE study and controls were assessed for 22 chronic cardiovascular health conditions. This assessment together with retrospective clinical reviews, were used to assign severity to conditions using a modified Common Terminology Criteria of Adverse Events (CTCAE) version 4.03 grading schema. The mean cumulative count, which treated death as a competing risk, was used to estimate cumulative burden.

Overall, 670 patients who survived 10 years or longer and reached the age of 18 years were treated at St Jude Children’s Research Hospital. Of these, 348 subjects were clinically assessed in the SJLIFE study and the remaining 322 eligible participants did not participate in SJLIFE. The age and sex frequency-matched SJLIFE community control cohort contained 272 subjects. The analysis compared the cumulative incidence of cardiovascular events occurring in the survivor and control cohorts by the age of 50 years.

The mean time from Hodgkin’s lymphoma diagnosis to the first SJLIFE clinical assessment was 23.1 years and the median was 22.2 years (range, 10.9 to 45.4 years).

While the average annual increase of grade 1 to 5 cardiovascular conditions was higher across all age brackets of SJLIFE-eligible survivors between the ages of 30 and 55 years compared to community controls, the grade 1 to 5 cumulative burden in survivors aged 50 years was nearly twice that of the control cohort.

The cumulative burden of grade 1 to 5 cardiovascular conditions experienced by age 50 per 100 survivors was 430.6 (95% confidence interval [CI] 380.7, 480.6) compared to 227.4 (95% 192.7, 267.5) per 100 individuals the control