title: Hydroxyurea in essential thrombocythemia: rate and clinical relevance of responses by European LeukemiaNet criteria.
abstract: A definition of response by cytoreductive therapy in essential thrombocythemia was recently provided by the European LeukemiaNet (ELN). Complete, partial, or no clinicohematologic responses were defined on the bases of platelet count, disease-related symptoms, spleen size, and white blood cell count. To provide estimates and clinical correlation of responses according to these criteria, we retrospectively examined 416 essential thrombocythemia patients treated with hydroxyurea for at least 12 months. Complete response, partial response, and no response were 25%, 58%, and 17%, respectively. Age more than 60 years and JAK2V617F mutation were significant predictors of response. After a median follow-up of 3.9 years, we registered 23 deaths, 16 hematologic transformations, and 27 thrombotic events (rate, 1.66% patients/year). Age, previous thrombosis, leukocytosis (white blood cell count > 10 x 10(9)/L), but not ELN responses, were independently associated with higher risk of thrombosis. The actuarial probability of thrombosis was significantly influenced by leukocytosis (P = .017) and not by platelet count, indicating that platelet number does not seem of prime relevance in the definition of ELN response.
authors.affiliation: Hematology Department, Ospedali Riuniti di Bergamo, Largo Barozzi 1, Bergamo, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carobbio
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Antonioli
authors.forename: Alessandro M
authors.initials: AM
authors.lastname: Vannucchi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barosi
authors.forename: Marco
authors.initials: M
authors.lastname: Ruggeri
authors.forename: Francesco
authors.initials: F
authors.lastname: Rodeghiero
authors.forename: Federica
authors.initials: F
authors.lastname: Delaini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rambaldi
authors.forename: Tiziano
authors.initials: T
authors.lastname: Barbui
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006918:Hydroxyurea / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D012074:Remission Induction; D012189:Retrospective Studies; D015996:Survival Rate; D013920:Thrombocythemia, Essential / Q000188:drug therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D006918:Hydroxyurea