Clinical Features of Myelodisplastic Syndromes in a Colombian Population: Retrospective Analysis of Two Large Referral Centers
Authors: Sossa Claudia Lucia , Abello Virginia , Peña Angela María , Salazar Luis Antonio , Rosales Manuel , Luna-Gonzalez Maria , Chalela Claudia Marcela , Reyes David Leonardo , Espinosa Katherine , Amaya María Alejandra , Gamboa-Cely Nestor , Sanchez-Sossa Luisa , Serrano Sergio , Espinosa Daniel , Casas Claudia Patricia , Jimenez Sara Ines , Sandoval-Sus Jose , Orozco Oviedo Carlos Alberto , Chen Xueyi , Solano Maria Helena 
Published: November 2020

Introduction: Myelodysplastic syndromes (MDS) comprise a varied group of clonal myeloid neoplasms characterized by cytopenias and an increased risk of progression to acute myeloid leukemia. Prognosis is variable, but little is known about the clinical features of MDS in the Colombian population. The diverseness of the disease and changes in standardized diagnostic criteria throughout the years have hinder accurate case detection and epidemiologic evaluation of MDS in our population.
Objective: The aim of the present study was to determine the clinical characteristics and evaluate the overall survival (OS) of patients with MDS treated at two large referral centers in Colombia.
Methods: An observational, retrospective study was conducted at two tertiary care centers in Colombia. Patients diagnosed with MDS at Clinica FOSCAL and Hospital San Jose between June 2013 and June 2019 were selected. Descriptive statistics were used to analyze baseline demographic characteristics and clinical data such as disease classification, risk stratification, and treatment. The Kaplan-Meier method was used to assess overall (OS) at 1, 3 and 5 years.
Results: A total of 96 patients were included. Median age at diagnosis was 75 years (range 31-104). Fifty-two (54.2%) patients were male. According to the 2016 World Health Organization classification of MDS, the most commonly diagnosed subtype was MDS with multilineage dysplasia (31.2%), followed by MDS with excess blasts (13.5%); however, 35.4% of patients had an unclassifiable MDS sub-type. Twenty-nine (31.2%) patients were screened for cytogenetic abnormalities, the most common chromosomal abnormalities were deletion in the long arm of chromosome 5 (4.2%) and deletion of 7q (2.1%). Therapy related MDS was diagnosed in 13 (13.5%) patients and secondary MDS associated to pesticides exposure in 2 (2.1%) patients.
After stratifying patients by the International Prognostic Scoring System (IPSS), the majority of patients were in the intermediate risk group, with 21 (34.4%) and 16 (26.2%) patients in the intermediate-1 and intermediate-2 categories respectively. Almost 80% of the patients presented one or more comorbidities, the most common was cardiac disease (30.5%).
Supportive care with erythropoiesis-stimulating agents was the most common first-line treatment (61.4%), followed by iron chelation therapy (6.2%). Forty-eight (50%) patients were treated with hypomethylating agents (HMA), 43.7% receiving azacytidine and 6.3% decitabine. Among HMA-treated patients, 49.6% were in the intermediate-2 and high-risk IPSS groups. Two patients underwent allogeneic hematopoietic stem cell transplantation. Only patients treated with HMA and cytarabine/idarubicin chemotherapy achieved a complete response (11.5%).
OS at one- and five-years post-diagnosis was 73.4% and 40.7% (95%CI 62.4-81.6 and 27.1-53.9) respectively. Patients in the intermediate-2 and high-risk IPSS groups had lower survival rates compared to those in the low and intermediate-1 risk groups. The OS for patients treated with azacytidine was 77.2% (95%CI 60.7-87.5%) at one-year, 43.2% (95%CI 23.9-61.1%) at three-years, and 37.8% (95%CI 19.0-56.5) at five-years after diagnosis. The most common cause of death was infection (51.3%), followed by disease progression (24.3%).
Conclusions: The OS of patients with MDS in our study is similar to the reported in the existing literature. Knowing the epidemiology, clinical characteristics, risk stratification, and disease outcomes of MDS patients in our population is crucial to decide the best treatment strategies and improve the clinical outcomes of our patients.

Disclosures
Sossa: Roche: Honoraria; Astellas: Honoraria; Takeda: Honoraria; Novo: Honoraria. Abello:Dr. Reddy's: Consultancy, Research Funding; Takeda: Honoraria, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Research Funding. Peña:Roche: Honoraria. Salazar:Novartis: Honoraria; Janssen: Honoraria. Sandoval-Sus:Celgene: Speakers Bureau; Massive Bio: Consultancy; Janssen: Consultancy; MorphoSys US: Consultancy.