tokens: Echocardiographic data from the experimental group of 21 patients ( mean age 16 + / - 5 years ) treated from 1 . 6 to 14 . 3 years ( median 5 . 3 ) before this study with 27 to 532 mg / m2 of doxorubicin ( mean 196 ) were compared with echocardiographic data from 12 normal age - matched control subjects .