Number of erythrocyte transfusions is more predictive than serum ferritin in estimation of cardiac iron loading in pediatric patients with acute lymphoblastic leukemia.

Transfusions with packed erythrocytes is a common practice in pediatric patients with acute lymphoblastic leukemia (ALL) who are on chemotherapy. Since there is no physiological excretion mechanism for iron, the iron related to erythrocyte transfusions accumulates and may contribute to late cardiac, hepatic and endocrine complications in these patients. In order to evaluate the iron burden among pediatric patients with ALL and define the risk factors associated with higher iron loading, we evaluated 79 pediatric patients with ALL (36 were off-therapy). Cardiac and hepatic T2* were ordered to a total of 22 (28%) patients who were either transfused with erythrocytes ≥ 10 times (n=11; 50%), had serum ferritin (SF) ≥ 1000 ng/ml (n=2; 9.1%) or both (n=9; 40.9%). Half of the patients who were screened by T2* MRI had hepatic T2*<7 ms and six (27%) of the patients had cardiac T2*<20 ms, indicating iron loading. Patients who had serum ferritin <1000 vs ≥ 1000 ng/ml had median cardiac T2* values of 28.3 ms (15-40) vs 21 (7.9-36), (p=0.324); whereas hepatic T2* of 10.8 (5.32-27) vs 4.7 (2.2-36), (p=0.017). Patients who had erythrocyte transfusion <10 vs ≥ 10 times had median cardiac T2* values of 34 ms (28-38) vs 23 (7.93-40), (p=0.021); whereas hepatic T2* of 13.6 (6.6-36) vs 5.32 (2.2-27), (p=0.046). Our results indicate that pediatric patients with ALL should be screened for transfusional iron load and the amount of erythrocyte transfusions seems to be a more reliable indication than serum ferritin levels to detect cardiac iron loading in these patients.