There was no difference in the rate at which children achieved complete remission after the first month of treatment (100% of children with Down syndrome vs 95.2% without).
With a median follow-up of 6.2 years, there was no statistically significant difference in 5-year rates of event-free survival (90.7% vs 83.7%), disease-free survival (90.7% vs 87.4%), or overall survival (91.8% vs 91.4%).
Patients with Down syndrome suffered more treatment-related mucositis (52% vs 12%), clots or bleeding (18.4% vs 8.2%), seizure (15.3% vs 4.7%), and infection (55.3% vs 41.3%).
Despite an elevated risk of toxicity from chemotherapy, children with Down syndrome and acute lymphoblastic leukemia (ALL) did not experience higher rates of relapse or treatment-related mortality compared with other children treated on Dana-Farber Cancer Institute ALL Consortium Protocols, according to research presented by Athale et al at the 58th American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 761).
Children with Down syndrome are at increased risk for developing ALL, but the optimal therapy for this group of patients has not been established. Dr. Silverman notes that previous studies have shown that children with Down syndrome have an increased risk of complications of treatment. Some studies have also reported that they have higher rates of relapse and/or treatment-related mortality, resulting in lower rates of long-term cure. Although the Dana-Farber protocol has never modified treatment for children with Down syndrome, Dr. Silverman added, other protocols have made dose-adjustments to minimize side effects.
There were no treatment-related deaths among the Down syndrome patients.
As has been reported in other studies, researchers found that the Down syndrome patients were less likely than other patients to present with T-cell ALL (none in the Down syndrome group vs 11.7% in non–Down syndrome patients) and high hyperdiploidy (8.8% vs 25.1%). The former is considered a higher-risk form of ALL, whereas the latter is associated with a more favorable prognosis, Dr. Silverman said.