Therapy-related acute myeloid leukemia after the treatment of primary solid cancer in children

Abstract

Therapy-related acute myeloid leukemia (t-AML) or therapy-related myelodysplastic syndrome (t-MDS) has a dismal prognosis and is one of the second malignant neoplasms, which could be encountered by pediatric oncologist more frequently. We have reviewed our experience with pediatric t-AML/t-MDS during a 17-year period. Between October 2000 and September 2016, 16 patients who had primary solid tumors were diagnosed with t-AML at the Seoul National University Childrens Hospital. The primary solid tumors assessed included osteosarcoma (n=5), neuroblastoma (n=2), Wilms tumor (n=2), Ewing sarcoma (n=2), medulloblastoma (n=1), pineoblastoma (n=2), rhabdomyosarcoma (n=1), anaplastic ependymoma (n=1), and a malignant germ cell tumor (n=1). The median patient age at the time of diagnosis of the primary solid tumors was 9.6 years (range, 0.1–15.4 years), and the median age at the time of diagnosis of t-AML was 14.0 years (range, 4.7–23.9 years). The crude estimated incidence rate of t-AML from pediatric primary solid cancer was 0.78%. The median latency period from the end of the primary tumor treatment to the diagnosis of t-AML/t-MDS was 29 months (range, 6–130 months). Fifteen patients received induction chemotherapy after the diagnosis of t-AML. Among them, only 12 patients achieved complete remission (CR). Of the 12 patients who achieved CR, only 7 patients underwent hematopoietic stem cell transplantation (HSCT). The 3-year and 5-year overall survival (OS) rates were 33.7 ± 12.2% and 25.2 ± 11.7%, respectively, and the 3-year and 5-year event-free survival rates were 26.9 ± 11.5% and 20.2 ± 10.4%, respectively. The patients who underwent HSCT showed favorable 5-year OS rates (57.1 ± 18.7%), while the 5-year OS rates of those who did not undergo HSCT was 0%. This study demonstrated that an achievement of CR and a subsequent HSCT can be the optimum solution for the treatment of t-AML, and this strategy showed an acceptable outcome. Screening patients who are susceptible to t-AML and preventing them from developing t-AML will be required in the future.