Childhood acute lymphoblastic leukemia in Nicaragua: Long-term results in the context of an international cooperative program

Background: The aim of this paper is to describe the results of acute lymphoblastic leukemia (ALL) treatment in Nicaragua from 1995 to 2005 in the context of an international cooperation program. Procedures: Patients <18 years with ALL were treated with two consecutive protocols (1995 and 2000). After a steroid prophase, a three-drug induction was administered in protocol 1995, and a four-drug induction, including asparaginase, was administered in protocol 2000. In protocol 2000, a modified BFM phase IB with cyclophosphamide, 6-mercaptopurine and cytosine arabinoside was administered to patients at high risk (HR), who also received IV methotrexate (500mg/m2) in the consolidation phase. Reinduction consisted of dexamethasone, vincristine, doxorubicin, cytosine arabinoside, and 6-thioguanine administered over 7 (protocol 1995) or 4 (protocol 2000) weeks; reinduction was repeated twice for patients at HR. Maintenance consisted of p.o. 6-mercaptopurine and methotrexate, and vincristine and dexamethasone pulses were added in the 2000 study. The total duration of therapy was 24 months. Results: In total, 540 patients were treated. Overall, 7% of patients died during induction, and 9% abandoned treatment. At 5 and 10 years from diagnosis, event-free survival (EFS) rates of 38.1% and 36.6%, respectively, and overall survival rates of 48.0% and 39.6%, respectively, were obtained, considering abandonment as an event. Conclusions: In our experience, a 10-year EFS of 36.6% was achieved in a country with limited resources. Factors limiting a higher success rate were treatment abandonment and a high relapse rate. Pediatr Blood Cancer 2014;61:827-832.