Childhood acute leukemia survivors with Down syndrome at higher risk for late mortality
Childhood acute leukemia survivors with Down syndrome had increased risk for late mortality not attributable to cardiac- or subsequent malignant neoplasm-associated late effects, according to study results published in Cancer.
“Although [childhood leukemia survivors] with Down syndrome were at greater risk for late effects such as hearing loss and cataracts compared with [survivors who did not have Down syndrome], this risk was not greater than that seen among Down syndrome controls, suggesting that these morbidities are related to the underlying Down syndrome and not leukemia treatment,” Sumit Gupta, MD, PhD, of the division of hematology/oncology at The Hospital for Sick Children in Toronto, and colleagues wrote.
Studies have shown children with Down syndrome have a 20-fold increased risk for developing acute leukemia compared with children without Down syndrome. However, cure rates for children with Down syndrome and leukemia have improved substantially during the past several decades, resulting in an increasing population of survivors.
During leukemia treatment, children with Down syndrome have an increased risk for acute toxicities, such as infections, mucositis and treatment-associated mortality. Individuals with Down syndrome are also more likely to develop other comorbidities as they age, regardless of cancer history, such as hearing loss and decline in cognitive function. The effect of these vulnerabilities on survivors of childhood leukemia with Down syndrome remained unknown.
Gupta and colleagues pooled data on all patients diagnosed with acute leukemia before age 18 years in Ontario, Canada, between 1987 and 2013. All patients survived more than 5 years since their last pediatric cancer event.
Researchers grouped patients into cohorts of those with or without Down syndrome, matched by birth year, sex, leukemia type and whether they underwent radiation.
They then matched cancer survivors who had Down syndrome with children who had Down syndrome without cancer (controls).
According to study results, the 79 childhood acute leukemia survivors with Down syndrome experienced lower 20-year OS compared with the 231 survivors without Down syndrome (81.7% vs. 98.3%; HR = 12.8; P < .0001) and 790 controls (96.3%; HR = 5.4; P < .0001).
Moreover, childhood acute leukemia survivors with Down syndrome experienced pulmonary and infectious deaths. Researchers observed no differences in incidence of congestive heart failure, hearing loss or dementia among childhood acute leukemia survivors with Down syndrome and the other comparative groups.
Based on these findings, further research examining the development of Down syndrome-specific survivorship guidelines is warranted, according to Gupta and colleagues.
“Our results suggest that such guidelines, based on information gleaned from the general survivor population, may not be applicable to Down syndrome survivors,” the researchers wrote. “Although Down syndrome-specific guidelines seem to be warranted, additional studies will be needed to determine what screening modalities and intervals will best improve the quality and quantity of survivorship for this population.”