Leucocytosis and thrombosis at diagnosis are associated with poor survival in polycythaemia vera: a population-based study of 327 patients.

Three hundred and twenty-seven patients from two population-based cohorts with an established diagnosis of polycythaemia vera were studied for prognostic risk factors for survival and leukaemia in a long-term survey. The relative survival (RS) was 72% and 46% at 10 and 20 years respectively, from the time of diagnosis. Multivariate analysis identified age >70 years, white blood cell count >13 × 10(9) /l and thrombo-embolism at diagnosis as independent risk factors. Patients with two or three of these factors had a 10 year RS of 26%, compared with 59% and 84% in patients with one and no risk factors, respectively. Age and leucocyte count are the main predicting factors for survival in polycythaemia vera.

Significant increase in the apparent incidence of essential thrombocythemia related to new WHO diagnostic criteria: a population-based study.

To observe the effect of the new World Health Organization (WHO) criteria on the incidence of myeloproliferative neoplasms, we performed a retrospective study of a population-based registry in the Côte d'Or area, France, from 1980 to 2007. A total of 524 myeloproliferative neoplasms were registered for the 1980-2007 period, including 135 polycythemia vera, 308 essential thrombocythemia and 81 idiopathic myelofibroses. No change in the incidence of either polycythemia vera or idiopathic myelofibrosis was observed for the 2005-2007 period, compared to 1980-2004. On the contrary, a pronounced increase in the incidence of essential thrombocythemia was noted after 2005, mainly due to the use of JAK2 mutation screening and a lower threshold of platelet count. Our study confirms the relevance of the new WHO diagnostic criteria in allowing earlier diagnosis of essential thrombocythemia.