Echocardiographic surveillance for asymptomatic late-onset anthracycline cardiomyopathy in childhood cancer survivors.

BACKGROUND: The optimal frequency of echocardiographic surveillance in asymptomatic childhood cancer survivors exposed to anthracyclines has not been established. We evaluated the effectiveness of performing surveillance echocardiograms according to the Children's Oncology Group's (COG) Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers in survivors ≥1 year from concluding therapy.
METHODS: We reviewed all children treated at our institution with anthracycline chemotherapy from 1995 to 2003. We assessed the frequency of abnormal echocardiograms according to risk groups defined in the COG guidelines, and evaluated the risk factors for an abnormal echocardiogram using Cox proportional hazards modeling.
RESULTS: At least one echocardiogram was completed by 469/603 (77.8%) eligible survivors. Mean diagnosis age was 7.7 (SD = 4.6) years. Mean cumulative doxorubicin-equivalent dose was 205 mg/m(2) (SD = 115). Survivors completed 1,013 echocardiograms (median  = 2, range =1-10) beyond 1 year after concluding therapy. Seventy-nine (16.8%) survivors had an abnormal echocardiogram at a median of 2.9 years (range 0.01-9.8) from 1 year after concluding therapy. Anthracycline dose >300 mg/m(2) (hazard ratio [HR] 3.00; 95% CI 1.51-5.98), age 1-4 years at treatment (HR 1.89; 95% CI 1.08-3.31) and radiation to a field involving the heart (HR 1.73; 95% CI 1.08-2.76) predicted an increased risk of an abnormal echocardiogram; however, even survivors in the lower COG risk groups demonstrated abnormalities.
CONCLUSION: Periodic echocardiographic surveillance in childhood cancer survivors can yield abnormalities that require further evaluation. Abnormalities may become evident as early as 1 year after the conclusion of therapy and can impact even those survivors considered to be at low risk.