The results of a registry study on acute myeloid leukemia in Russian children

Le résumé fourni par la source

We conducted a prospective observational registry study at the Dmitry Rogachev National Medical Research Center aiming to evaluate acute myeloid leukemia (AML) treatment and its outcomes in children in regional oncology/hematology centers of Russia as well as to report the results. The study was approved by the Independent Ethics Committee and the Scientific Council of the The Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. We enrolled a total of 380 patients (205 boys and 175 girls) with newly diagnosed AML with the median age of 6.6 years (52 days to 18 years) and the median white blood cell count at disease onset equaling 17.7 (0–540) × 109/L. Fifty-two patients (13.6%) had WBC count greater than 100 × 109/L (hyperleukocytosis), 55 patients (14%) presented with neuroleukemia, and 60 (16%) had extramedullary lesions. The enrolled patients were stratified into a standard risk (92 patients), intermediate risk (99) or high risk (189) group. The first clinical and hematological remission (CR1) was achieved in 324 patients (85%), with early mortality rate reaching 8.4%. The median follow-up of the survivors was 8.3 years (1.5 months to 11.5 years). The 5-year overall survival (OS) in the entire cohort was 0.60 ± 0.025, the 5-year event-free survival (EFS) – 0.42 ± 0.025, and the cumulative incidence of relapse (CIR) – 0.37 ± 0.027. Initial extramedullary lesions (OS 0.47 ± 0.06 and EFS 0,37 ± 0.06) and hyperleukocytosis (OS 0.47 ± 0.07 and EFS 0.25 ± 0.06) led to a poorer prognosis in the AML patients, but CIR was not affected by these factors. The lowest OS rate was observed in the patients with monosomy 7 and with t(10;11)(p11-15;q21)/PICALM::MLLT10, totaling 0.2 ± 0.2 and 0.14 ± 0.1, respectively. Hematologic stem cell transplantation (HSCT) performed in CR1 significantly improved OS (0.84 ± 0.05), EFS (0.77 ± 0.06) and CIR (0.18 ± 0.05) in the high-risk patients. The majority of allogeneic HSCTs were performed using cells from haploidentical (51%), unrelated (25%) and genoidentical donors (18%). In the 50 patients treated with HSCT while in active disease, the OS was 50%. Out of 189 high-risk patients, only 67 (35%) underwent HSCT in CR1. The OS and EFS of the patients from regions were 0.51 ± 0.033 and 0.38 ± 0.032, respectively. The CIR was 0.36 ± 0,04. Relapses were reported in 37% of the patients who had achieved СR1. A total of 157 (41%) patients died during the study, out of which 112 patients had been treated at regional hospitals. The OS in the AML pediatric patients in Russia was 60%. The main treatment failures were toxic deaths (16%) and relapses (37%). In 2018, healthcare professionals of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology developed the AMLMRD-2018 protocol that could also be implemented in regional clinics, aiming to reduce toxic (infectious) death rates and thus increase the OS by at least 10% as well as to ensure HSCT accessibility for all high-risk patients.

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