Observation is appropriate for this patient with low-risk myelodysplastic syndrome (MDS), incidentally discovered by a complete blood count showing asymptomatic pancytopenia. The mild macrocytosis is typical. The bone marrow biopsy is appropriate to confirm a suspected diagnosis of myelodysplasia in the setting of the normal vitamin B12 and folate levels and to provide important prognostic information. This patient has low-risk disease by the revised International Prognostic Scoring System criteria despite two involved cell lines. The low-risk cytogenetics and low marrow blasts (<2%) indicate very low-risk MDS. Median survival is 8.8 years in a generally older adult population and the median time to 25% acute myeloid leukemia (AML) progression is more than 14 years. No therapy will improve prognosis in this situation.
5-Azacytidine is appropriate therapy for higher risk MDS for the purpose of improving blood counts, delaying AML progression, and extending survival. It would be indicated to lessen transfusion dependence or to improve prognosis for high-risk disease, but is inappropriate in this patient, whose disease is low risk.
Allogeneic hematopoietic stem cell transplantation is not justified, because this patient's disease is very low risk. In contrast, a patient with very high-risk disease has an expected median survival of less than 1 year, justifying the treatment-related morbidity associated with transplantation.
Erythropoietin is inappropriate because this patient is asymptomatic. Recombinant erythropoietin can be effective in approximately 25% of patients with MDS. However, the goal hemoglobin level is 10 g/dL (100 g/L), and targets to higher values have been associated with arterial and venous thrombosis.