Early detection of cardiotoxic side effects of anthracyclines with the use of N-terminal pro-BNP and six-minute walk test in childhood cancer patients

Despite the fact that the number of pediatric cancer patients rapidly increasing each year, the most cost-effective cardiac follow-up test is still unknown. The significance of pro-BNP and six-minute walk test in the follow-up of pediatric cancer patients who accomplished chemotherapy and out of clinical cardiotoxicity, has been investigated in this study. Pro-BNP levels were measured in the serum samples of 16 patients who have no symptoms of heart failure and completed their chemotherapy between 9 and 16 years ago, and 16 healthy control subjects. The day after, six-minute walk test was performed according to American Thorax Society recommendations. According to results; patients treated with anthracyclines have higher serum pro-BNP levels than control subjects (p:0,051). As cumulative anthracycline dosage increases the levels of pro-BNP are elevated with a high correlation rate (p:0,02); and the difference between two groups is getting statistically significant when the cumulative dosage exceeds 250 mg/m2 (p:0,016). As cumulative anthracycline dosage increases the distance in six-minute walk test decreases (negative correlation p:0,092) but there is no statistically significant difference between the patients who received chemotherapy with a cumulative dosage more than 250 mg/m2 and the ones who had none (p:0,076). In all countries it is very difficult to reach pediatric cancer patients after completing their chemotherapy. Moreover, six-minute walk test is newly becoming familliar in pediatricians in our country. Eventually, the value of pro-BNP and six-minute walk test in the follow-up of pediatric cancer patients should be studied and supported with following studies.Key Words: anthracycline cardiotoxicity, six-minute walk test, pro-BNP