Exercise echocardiography in asymptomatic survivors of childhood cancer treated with anthracyclines: a prospective follow-up study.

BACKGROUND

Exercise echocardiography reveals abnormalities in asymptomatic childhood cancer survivors who previously have been treated with anthracyclines. We determined the added value of monitoring childhood cancer survivors with exercise echocardiography compared to monitoring with resting echocardiography alone to predict anthracycline-induced cardiotoxicity. Secondary aims were to evaluate change in resting cardiac function over 10 years and to determine risk factors for late cardiotoxicity.

PROCEDURE

We invited a cohort of 110 originally asymptomatic anthracycline-treated childhood cancer survivors, who had undergone cardiac tests including exercise echocardiography 10.5 years earlier, for new cardiac evaluation. Each subject underwent a resting echocardiogram at both evaluations. At first evaluation a repeat echocardiogram was performed following peak exercise. Resting echocardiographic parameters were converted to z-character.

RESULTS

Ninety-two of 110 survivors (mean anthracycline dose 307 mg/m(2), mean follow-up time from start of treatment 8.2 years at first and 18.8 years at second evaluation) were evaluated prospectively. Mean resting fractional shortening z-character (RFSz) decreased from -0.18 to -0.93. Higher cumulative anthracycline dose was a risk factor for a lower RFSz at late follow-up (P = 0.0002). Adding exercise fractional shortening (XFS) to a model containing RFSz did not improve prediction of abnormal RFSz at late follow-up.

CONCLUSIONS

Monitoring with exercise echocardiography has no added value to monitoring with resting echocardiography alone in predicting late anthracycline-induced cardiotoxicity in childhood cancer survivors. RFSz deteriorates over time, even in originally asymptomatic patients. Previous treatment with higher cumulative anthracycline dose is the main risk factor for a lower RFSz at late follow-up.