Adult survivors of childhood cancer have a high risk of cardiovascular disease but the risk is often unrecognised and undertreated, new research shows.
People who have had cancers such as leukaemia in childhood face up to five fold higher risks of cardiovascular disease in adulthood due to their exposure to chemotherapy and radiation therapy, according to a paper published in the Journal of the American Heart Association.
The authors said blood cancer survivors have a greater burden of modifiable CVD risk factors such as hypertension, dyslipidemia, and diabetes compared with the general population, and also tend to develop CVD risk factors at younger ages.
“These modifiable risk factors appear to be synergistic with the cardiotoxic effects of cancer treatments and potentiate survivors’ risk of ischaemic heart disease and heart failure more than they do in the general population,” they wrote.
To investigate cardiovascular risks and management in current practice they followed up 571 patients who had been been diagnosed with cancer before age 21 and enrolled in the Childhood Cancer Survivor Study .
The participants (median age 37 years) underwent assessment for cardiovascular risk factors such as hypertension and dyslipidaemia at an average of 28 years after cancer diagnosis, with results compared with a control group of 350 age-matched adults without a history of cancer.
Cancer survivors were more likely than those without a history of cancer to have hypertension (18% vs. 11%, respectively), abnormal lipid levels (14% vs. 4.9%, respectively) and diabetes (6.5% vs. 3.2%, respectively).
Participants in both groups had similar rates of underdiagnosed hypertension, high cholesterol and diabetes: 27.1% among cancer survivors and 26.1% among the comparison group.
However, cancer survivors were 80% more likely to be undertreated for these conditions compared to their study counterparts (21.0% versus 13.9%).
The most underdiagnosed and undertreated risk factors were hypertension (18.9%) and dyslipidaemia (16.3%), respectively.
Men and people who were overweight/obese were more likely to be underdiagnosed and undertreated for cardiovascular risk after surviving cancer. Those with multiple adverse lifestyle factors were also more likely undertreated (odds ratio, 2.2, 95% CI, 1.1–4.5).
The most common cancers in childhood in the study participants were leukaemia (34%), lymphoma (25%) and bone cancer/sarcoma (15%). Three quarters (77%) had been exposed to anthracycline chemotherapy and 43% had radiation exposure in childhood.
The study authors noted that current guidelines for long-term follow-up of cancer survivors recommend annual measurement of blood pressure and regular (every two years) screening of lipid profiles and glucose metabolism among those exposed to abdominal radiation, or if comorbid CVD risk factors are present.
For survivors who received anthracyclines or chest radiation, routine echocardiography to monitor for early-onset cardiomyopathy also is recommended.
“These findings make underdiagnosis and undertreatment significant concerns for the estimated half a million childhood cancer survivors living in the United States,” said lead study author Dr Eric Chow, associate professor in clinical research and public health sciences at the Fred Hutchinson Cancer Center in Seattle.
“Serious heart disease is uncommon in young adults in the general population, which includes childhood cancer survivors, therefore, greater awareness of the significantly higher cardiovascular disease risk when there is a history of cancer is important,” he said.
“Raising awareness among primary care professionals as well as improving survivors’ ability to self-manage their health may mitigate the increased risks. There are specialised heart disease risk calculators designed for cancer survivors, and those may be more accurate in predicting future cardiovascular disease risk than risk calculators designed for the general population,” Dr Chow added.