Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases of the bone marrow, characterized by cytopenia and an increased risk for transformation to acute myeloid leukemia (AML). For patients with high-risk MDS, hypomethylating agents have been implemented recently as 5-Azacitidine (5-AZA) in order to improve the overall survival (OS), and additionally the decreased transfusion requirement and the delayed AML progression to AML. At present, 5-AZA is a drug used in our country, so that the analysis of MDS patients treated with this drug in the Centro Médico Nacional “20 de Noviembre”, will reveal the clinical benefits and their contribution in the overall survival (OS). Objective: Learn about the therapeutic response in MDS patients treated with 5-AZA. Secondly, OS and EFS, as well as toxicity will be established. Patients and Methods: Prospective, experimental, longitudinal, single-center, single-arm study. Patients diagnosed with MDS, treated with 5-AZA at 100 mg/day for 7 days with at least 4 cycles, attended at the Hematology Service of CMN “20 de Noviembre”, from 2010 to 2015. Results: 15 patients with MDS diagnosis, treated with 5-AZA, were assessed. The mean age was 64 years, 60% were women and 40% men. Seven percent (7%) of all patients were diagnosed with refractory anemia with ring sideroblasts; 7% with refractory cytopenia with multilineage dysplasia, 27% with refractory anemia with excess blast 1 (AREB-1), and 60% with refractory anemia with excess blast 2 (AREB-2). The cytogenic risk was good in 67%, intermediate in 7% and highly complex in 27%. Regarding prognostic indices, 27% of the patients were classified by IPSSS as intermediate 1, 53% as intermediate 2, and 20% as high risk. For the IPSS-R, 33% was intermediate risk, 40% high risk, and 27% very high risk. The analysis of the response to treatment was performed by measuring hemoglobin, absolute neutrophils, platelets, number of bone marrow blasts, number of peripheral blood blasts and DHL upon diagnosis, the 4th treatment cycle, and 9th treatment cycle. 33% complete response (CR), 13% partial response (PR), 7% stable disease (SD), and 47% failure were obtained. A relapse was observed in 13% of the patients, and progression to acute myeloid leukemia (AML) in 49%. In the multivariate analysis, the factors having an impact on the response were IPSS score, with p=0.015; IPSS-R with p=0.05. The median overall survival (OS) was 17 months. No patient presented renal or hepatic toxicity. The number of hospitalization days per the risk was a median of 8.5 days for INT1, median of 13 days for INT-2, and a median of 12 days for HIGH (p=0.032). The median number of times the patient had febrile neutropenia according to risk INT1, INT2 and HIGH was 3.5, 6 and 8 times, respectively (p=0.014). The median transfusion requirement was 25 concentrated erythrocytes (CE), and the transfusion requirement according to the degree of response was 12 CE for CR, 10 CE for PR, 16 CE for EE, and 19 CE for failure (p=0.06). Conclusions: The treatment with 5-AZA has demonstrated to extend OS in patients with MDS diagnosis, especially those with high risk. In our study a 17-months OS was shown, which is comparable to that reported in the literature5. Likewise, it has been associated with a reduced transfusion requirement and, thus, a quality-of-life benefit for MDS patients. Therefore, 5-AZA is considered a treatment of choice in MDS patients not being candidates for intensive chemotherapy in the daily clinical practice.
