Evaluation of Cytopenias Occurring in Imatinib Treated Chronic Myeloid Leukemia (CML) Patients

Imatinib Mesylate, a Tyrosine Kinase inhibitor, is presently the drug of choice for Chronic myeloid leukemia (CML). During therapy, a few patients develop myelosuppression and present with cytopenias. To study the bone marrow morphology in imatinib treated CML patients presenting with persistent cytopenias. The cases were retrieved from the Hematopathology record files, Department of Pathology; the study period being January 2008-June 2009. Cases of CML on Imatinib presenting with grade 2 or more anemia, neutropenia and/or thrombocytopenias with bone marrow studies, were included in the study. The morphology of all cases was reviewed with cytogenetic studies. Follow-up details were obtained from the Medical Oncology records. During the study period, 683 Imatinib treated CML patients had bone marrow studies as part of their follow-up investigations. Of these, 60 patients (9%) had some form of persistent cytopenia. The patients ranged from 21 to 75 years of age with a median age of 38 years. The male:female ratio was 1:1. There were 46 patients with ≥grade 2 anemia, 25 patients with ≥grade 2 neutropenia and 37 patients with ≥grade 2 thrombocytopenia. Of these, 18 patients had bicytopenia and 13 cases had pancytopenia. The marrow evaluation revealed morphologic response in 30 patients, persistent marrow disease in five patients, marrow hypoplasia in six patients, extensive stromal changes including fibrosis in five patients, megaloblastic erythropoiesis in 11 patients and disease progression to accelerated or blast crisis in three patients. Various degrees of cytopenias may occur in few patients of CML on imatinib therapy. Regular hematologic follow-up is required so that the drug may be stopped or dose modified as per the individual's needs.