Polycythemia vera and essential thrombocythemia: 2015 update on diagnosis, risk‐stratification and management

Abstract

Disease overview: Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms, respectively characterized by erythrocytosis and thrombocytosis. Other disease features include leukocytosis, splenomegaly, thrombosis, bleeding, microcirculatory symptoms, pruritus, and risk of leukemic or fibrotic transformation. Diagnosis: PV is defined by a JAK2 mutation, whose absence, combined with normal or increased serum erythropoietin level, makes the diagnosis unlikely. Differential diagnosis in ET includes reactive thrombocytosis, chronic myeloid leukemia, and prefibrotic myelofibrosis. Janus kinase 2 (JAK2), calreticulin (CALR), or myeloproliferative leukemia virus oncogene (MPL) mutations occur in approximately 55%, 25%, and 3% of ET patients, respectively. The same molecular markers are also present in prefibrotic myelofibrosis, which needs to be morphologically distinguished from ET. Survival and leukemic/fibrotic transformation: Median survivals are ∼14 years for PV and 20 years for ET; the corresponding values for younger patients are 24 and 33 years. Life‐expectancy in ET is inferior to the control population. JAK2/CALR mutational status does not affect survival in ET. Risk factors for survival in ET and PV include advanced age, leukocytosis, and thrombosis. Leukemic transformation rates at 20 years are estimated at <10% for PV and 5% for ET; fibrotic transformation rates are slightly higher. Thrombosis risk stratification: Current risk stratification in PV and ET is designed to estimate the likelihood of recurrent thrombosis: high‐risk is defined by the presence of age >60 years or presence of thrombosis history; low‐risk is defined by the absence of both of these two risk factors. Recent data consider JAK2V617F and cardiovascular risk factors as additional risk factors. Presence of extreme thrombocytosis might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding. Risk‐adapted therapy: The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. In low risk patients, this is accomplished by the use of low‐dose aspirin and phlebotomy (hematocrit target <45%) in PV. In high risk (for thrombosis) patients, treatment with hydroxyurea is additionally recommended. Treatment with busulfan or interferon‐α is usually effective in hydroxyurea failures and the additional value of JAK inhibitor therapy in such cases is limited. Screening for AvWS is recommended before administrating aspirin, in the presence of extreme thrombocytosis. Am. J. Hematol. 90:163–173, 2015. © 2014 Wiley Periodicals, Inc.

Myeloproliferative neoplasms: A decade of discoveries and treatment advances

“…The utilization of aspirin therapy in PV is supported by controlled evidence [83], which has also been used as a rationale to treat ET patients with arterial risk factors [112]. In terms of cytoreductive therapy, there is controlled evidence of value for chlorambucil or radiophosphorus in PV [113], and hydroxyurea in high risk ET [85].…”

“…The JAK inhibitor ruxolitinib was recently approved for use in hydroxyurea-intolerant/resistant PV, based on its ability to alleviate constitutional symptoms and reduce spleen size [121]. However, the drug has not been shown to modify the natural history of PV and carries significant short-term and longterm side effects [122] that undermine its utility and it is currently not recommended for use in PV, in the absence of refractory symptomatic splenomegaly or intractable pruritus that fail to respond to hydroxyurea, busulfan or interferon alfa [112].…”

Clinico-Hematological Profile and Risk Stratification in Patients with Essential Thrombocythemia: Experience from Pakistan

“…Survival of ET patients does not considerably reduce having the median survival of around 20 years (Tefferi and Barbui, 2015). However life-expectancy in ET patients is inferior to the control population (Tefferi and Barbui, 2015).…”

“…However life-expectancy in ET patients is inferior to the control population (Tefferi and Barbui, 2015). Nonetheless, important morbidity is derived from vascular disturbance, including thrombosis, microvascular complications and bleeding (Posfai et al, 2015).…”

Somatic JAK-2 V617F Mutational Analysis in Polycythemia Rubra Vera: a Tertiary Care Center Experience

“…JAK2V617F has been recognized in varied subsets of each Ph-chromosome negative MPNs (Duangnapasatit et al, 2015). Various studies have demonstrated that this mutation is present in more than 95% of the patients with PV and in 55 and 65% of patients with ET and PMF respectively (Tefferi et al, 2015). Therefore, determination of JAK2V617F mutation is potentially diagnostic tool for PV patients.…”