Treatment cardiotoxicity reduction pays late dividends after childhood cancer
medwireNews: Efforts to reduce the cardiotoxicity of cancer treatment in childhood appear to have paid dividends, report researchers.
Their study of 34,489 British childhood cancer survivors diagnosed between 1940 and 2006 shows an overall 3.4-fold increased number of cardiac deaths relative to that expected in the general population, equating to 2.1 excess cardiac deaths per 10,000 person–years.
The highest risk occurred during the 1980s, Michael Hawkins (University of Birmingham, UK) and team report in Circulation. Patients diagnosed during this time were 2.3 times more likely to later die of cardiac causes than those diagnosed before 1970, after accounting for age, attained age, and tumor type.
The researchers believe this reflects the effects of “anthracycline chemotherapy, which has been shown to increase the risk of dilated cardiomyopathy and congestive heart failure.” But they stress that “it is important to recognize that many more children diagnosed with cancer in the 1980s have survived as a result of anthracycline chemotherapy than have died due to its late effects.”
And patients diagnosed between 1990 and 2006 were no more likely to die of cardiac causes than those diagnosed before 1970, suggesting the success of “measures to reduce cardiotoxicity through using alternative drugs, lowering cumulative doses, and improved monitoring and intervention.”
Cardiac deaths accounted for only a small proportion of the excess deaths among patients younger than 60 years, with recurrence/progression or new primary neoplasms being the dominant causes. But cardiac causes and other circulatory causes accounted for a respective 21.9% and 14.9% of the excess deaths among older patients.
The study authors say this reflects mortality patterns in the general population. However, they note that the frequency of these mortality causes, and new primary neoplasms accounting for a further 31.4% of deaths, suggest the need for “specific interventions, in terms of surveillance and treatment,” to limit premature mortality in survivors of childhood cancer.
Patients with Hodgkin’s lymphoma and Wilms tumor (nephroblastoma) had the highest risk for cardiac mortality, collectively accounting for nearly 30% of the 181 cardiac deaths in the cohort.
However, Hawkins et al stress that patients who survived to the age of at least 60 years in their study “are quite different from those more recently diagnosed in terms of both [first primary neoplasm] types and treatment exposures,” which necessitates continued assessment of mortality risk and causes in these long-term cancer survivors.
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