Experience of management of patients with acute promyelocytic leukemia (APL) in Armenia.

Abstract Introduction. Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia caused by specific translocation between chromosomes 15 and 17 (15;17) which results in PML/RARA fusion. Disease is characterized by blocked myeloid progenitor cell differentiation and accumulation of promyelocytes in the bone marrow. Hemorrhagic syndrome and thrombotic events are typical clinical presentations of APL. Aim. This retrospective study was conducted to analyze the clinical, demographic, laboratory data of patients with APL in Armenia, as well as to evaluate treatment outcomes, mortality and overall survival rates. Patients and methods. Patient data were retrieved from the national cancer registry for acute myeloid leukemia. We analyzed the records of all patients (including pediatric patients) diagnosed with APL at our center between January 2017 and December 2024. Patient data included age, laboratory analyses (such as white blood cell count, blast count, and cytogenetic analysis results), treatment regimens, complications, minimal residual disease (MRD) results, treatment outcomes, date of death, loss to follow-up, and survival status. The retrospective analysis was performed using descriptive and survival analysis methods. Results. During the period between January 2017 and December 2024, 38 patients were diagnosed with APL of which 5 were children. The median annual incidence was 0.14 case per 100.000 population. The median age at diagnosis was 42 years old. Male patients' number was 22 (57,8%). Twenty-two patient (57,8%) had low risk, thirteen patient (34,2%) high risk disease. The main part of adult patients independent of risk group (n=22) received treatment with ATRA+ATO regimen, 3pts with (7+3) +ATRA, 1 patient with ATRA+ Idarubicin, 2 high risk pts with APML-4, 5 patients did not receive antileukemic treatment, 5 pediatric patients received treatment with APL-BFM 2013 and PETHAEM/HOV 2005+ATRA.Thirty patients experienced complete remission (CR). MRD was evaluated in 11pts. Early death, identified as death within 30 days of hospitalization, was observed in 8 patients (21%) of which 5 pts died before the initiation of chemotherapy. In all patients cause of death were different type of hemorrhagic complications. Only two pediatric patients experienced relapse, one of them died before initiation of second line therapy, while the other developed relapse in the form of T-lymphoblastic leukemia and is in CR after treatment. Median follow up time was 25 months, at last contact 26 pts were alive in remission, status of 3 pts was unknown. Kaplan–Meier survival analysis showed that the median survival time was not reached, as the survival probability remained above 50% throughout the follow-up period. At 25 months, the estimated survival probability was approximately 75%, with a 95% confidence interval (CI: 57.5%–86.2%).Conclusion. This study highlights several challenges in the management of APL patients in Armenia. Despite a high rate of hematologic response, early mortality remains a significant issue, underscoring the need for improvements in early diagnosis and supportive care. The low proportion of patients with minimal residual disease (MRD) monitoring is primarily due to the lack of quantitative PCR (qPCR) availability in Armenia. Implementing routine qPCR testing for MRD in APL patients is a critical step to improve disease monitoring and long-term outcomes. Enhanced early detection and comprehensive supportive care strategies are essential for improving survival rates among APL patients in Armenia.