Trends in the incidence of polycythemia vera among Olmsted County, Minnesota residents, 1935-1989

Polycythemia vera in pregnancy represents a challenge for a multidisciplinary collaboration: A case report and literature review

Polycythemia vera (PV) is a rare chronic myeloproliferative neoplasm which represents an additional thrombotic factor in pregnancy. PV may be difficult to diagnose, particularly as its incidence is extremely uncommon among young women. The main diagnostic method involves a bone marrow biopsy, and high hemoglobin and platelet counts are usually indicative of the condition, after excluding other more frequent pathologies. PV is associated with a high risk of thrombosis, particularly in pregnancy, and requires anti-platelet treatment. At present, only a limited number of PV cases in pregnancy have been reported in the literature, at least to the best of our knowledge, with the largest case series being a retrospective study that included 25 pregnancies in 15 women. The present study describes the case of a patient diagnosed with JAK2-positive PV and also discusses this rare condition with particular focus on the following: i) The management of PV in pregnancy along with the additional pathologies in this specific case; and ii) the particularities of the pregnancy course. By identifying women suffering from PV superimposed by other possible procoagulant factors and applying the latest standard in healthcare, fetal and maternal prognosis may be significantly improved.

Incidence of myeloproliferative neoplasms - trends by subgroup and age in a population-based study in Sweden

BACKGROUND

The reported incidence of Philadelphia-negative myeloproliferative neoplasms (MPNs) differs substantially between previous reports, likely due to true regional differences in incidence and/or variations in the quality and coverage of the cancer registers.

OBJECTIVE

We therefore assessed MPN incidence in Sweden during recent years using prospectively collected information captured in Swedish health registers.

METHODS

Patients with MPNs were identified through the Swedish Cancer Register and Swedish Blood Cancer Register between 2000 and 2014. Information on the Swedish population was obtained from the Human Mortality Database. Crude and age-standardized incidence rates of MPNs with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 6281 MPN cases were reported to the Swedish Cancer Register and Swedish Blood Cancer Register during 2000-2014. The age-standardized, to the Swedish population in 2000, incidence for all MPNs was 4.45 (95% confidence interval [CI] 4.34-4.56)/100 000 person-years. The age-standardized incidence for polycythemia vera was 1.48 (1.42-1.54), for essential thrombocythemia 1.60 (1.53-1.66) and for primary myelofibrosis 0.52 (0.48-0.56)/100 000 person-years, respectively. The incidence rate of MPNs was substantially higher in the older compared to the younger age groups. The incidence increased during the study period, likely to do better reporting and increasing age of the general population.

CONCLUSION

The reported MPN incidences in our study, which were in the higher interval of previously published studies, are likely more accurate compared to previous reports due to the population-based setting and high level of coverage in the Swedish Cancer and Blood Cancer Registers.

Perioperative management of polycythemia vera with advanced gastric cancer: A case report

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We report a case involving operation for gastric cancer after treatment for PV.

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Control of WBC and Plt counts during the perioperative period led to good results.

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Perioperative management for PV is important for complication-free surgery.

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Careful follow up should be performed for gastric cancer and PV recurrence.

Introduction

Polycythemia vera (PV) is a chronic myeloproliferative disorder with generally good prognosis. However, thrombotic and cardiovascular complications are among the leading causes of death in patients with PV and sufficiently effective management strategies are yet to be established. We report a case involving operation for gastric cancer in a patient being treated for PV.

Presentation of case

A 73-year-old man was diagnosed as PV on the basis of abnormal laboratory data eight years previously. Three months ago, he was referred to our department for anorexia and melena. The preoperative diagnosis was advanced gastric cancer, Stage IIB. To avoid perioperative thrombotic and hemorrhagic events, low-dose aspirin administration was continued with an additional dose of hydroxyurea. Emergent control was necessary because of the severity of gastric cancer symptoms, including pyloric stenosis and anemia. Distal gastrectomy with D2 lymph node resection was performed. The postoperative course was satisfactory, and the patient is currently doing well without any signs of recurrence or hematological complications.

Discussion

We described the successful management of a patient being treated for PV who underwent gastrectomy. As mentioned earlier, thrombotic complications and hemorrhage during the perioperative period are the major risk factors in patients with PV. In this case, control of white blood cell and platelet counts during the perioperative period led to good results.

Conclusions

Perioperative management for PV is important for complication-free surgery. Careful follow up should be performed for gastric cancer and PV recurrence.

3023 Mayo Clinic Patients With Myeloproliferative Neoplasms: Risk-Stratified Comparison of Survival and Outcomes Data Among Disease Subgroups

OBJECTIVE

To document the Mayo Clinic decades-long experience with myeloproliferative neoplasms (MPNs) and provide mature risk-stratified survival data and disease complication estimates.

PATIENTS AND METHODS

All Mayo Clinic patients with World Health Organization-defined MPNs constituted the core study group and included those with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF).

RESULTS

A total of 3023 consecutive patients (median age, 62 years; range, 18-96 years) were considered: 665 PV, 1076 ET, and 1282 PMF. From October 27, 1967, through December 29, 2017, 1631 deaths (54%), 183 leukemic transformations (6%), 244 fibrotic progressions (14%), and 516 thrombotic events (17%) were recorded. Median overall survival (OS) was 18 years for ET, 15 years for PV, and 4.4 years for PMF (P<.05 for all intergroup comparisons). Inferior survival was documented in patients with ET diagnosed more recently (post-1990) (P<.001), whereas survival data were time independent in PV and PMF. After conventional risk stratification, OS in low-risk ET and low-risk PV were superimposed (P=.89) but each differed significantly from that of age- and sex-matched controls (P<.001). Leukemia-free survival was similar for ET and PV (P=.22) and significantly worse with PMF (P<.001). Compared with ET, PV was associated with higher risk of fibrotic progression (P<.001). Thrombosis risk after diagnosis was highest in PV and lowest in PMF (P=.002 for PV vs ET; P=.56 for ET vs PMF; and P=.001 for PV vs PMF).

CONCLUSION

This study provides the most mature survival and outcomes data in MPNs and highlights MPN subgroup risk categorization as key in appraising disease natural history. The OS was only marginally better in ET compared with PV, and PV displayed a higher risk of thrombosis and fibrotic progression.

Austrian recommendations for the management of polycythemia vera

Polycythemia vera (PV) is a clonal disease arising from hematopoietic stem cells. Erythrocytosis is the hallmark of the disease but leukocytosis, thrombocytosis and splenomegaly may also be present. Thromboembolic complications occur in about 20% of patients. Circulatory disturbances as well as pruritus represent frequent symptoms of the disease. Mutations in the JAK2 gene are present in 95% of patients in exon 14 (V617F) and in 3% in exon 12. The main goal of the treatment for patients with PV is the prevention of thromboembolic events, transformation to myelofibrosis and acute myeloid leukemia. Interferon alpha and hydroxyurea are used as first-line treatment for high risk patients. For patients unresponsive to first-line therapy ruxolitinib is available.

Direct observation of Medicaid beneficiary attempts to fill prescriptions for nicotine replacement medications

OBJECTIVES

Although many states have expanded Medicaid coverage of cessation medications, utilization remains low. Anecdotal reports suggest that beneficiaries are at times denied coverage of cessation medications at the pharmacy counter. We conducted an observational community-wide case study of Medicaid beneficiary attempts to fill over-the-counter nicotine replacement therapy at pharmacies.

METHODS

We recruited tobacco-using beneficiaries from a Federally Qualified Health Center, whose providers wrote paper prescriptions for nicotine patches. Study staff escorted beneficiaries to all eligible pharmacies (n = 18) in a Midwestern community to observe fill attempts. Study staff recorded encounters via smartphone into a secure database on a university server.

RESULTS

Seven of 18 pharmacies (39%) did not fill the prescription on the day of the attempt. Of these, 6 offered to order the patch for pick-up at a later date. All (4/4) chain pharmacies filled the prescription; 2/3 mass merchant pharmacies failed to fill. Combining successful same-day fills with offers to order for pick-up, 17/18 (94%) would ultimately have been able to obtain patches.

CONCLUSION

This pilot study found that many beneficiaries left pharmacies without a prescription in hand. Successful same-day fills varied markedly by store type. For people with low incomes, transportation presents a major barrier for delayed pick-up. In addition, delays can fuel ambivalence toward quitting. Future research based on this pilot study might address whether patients who fail to secure a same-day prescription ever fill the prescription and, if not, the degree to which this barrier contributes to success or failure in quitting.

The impact of myeloproliferative neoplasms (MPNs) on patient quality of life and productivity: results from the international MPN Landmark survey

Myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET) are myeloproliferative neoplasms (MPNs) associated with high disease burden, reduced quality of life (QOL), and shortened survival. To assess how MPNs affect patients, we conducted a global MPN Landmark survey. This online survey of patients with MPNs and physicians was conducted in Australia, Canada, Germany, Japan, Italy, and the United Kingdom. The survey measured MPN-related symptoms and the impact of MPNs on QOL and the ability to work as well as disease-management strategies. Overall, 219 physicians and 699 patients (MF, n = 174; PV, n = 223; ET, n = 302) completed the survey; 90% of patients experienced MPN-related symptoms. The most frequent and severe symptom was fatigue. Most patients experienced a reduction in QOL, including those with low symptom burden or low-risk scores. A substantial proportion of patients reported impairment at work and in overall activity. Interestingly, physician feedback and blood counts were the most important indicators of treatment success among patients, with improvements in symptoms and QOL being less important. Regarding disease management, our study revealed a lack of alignment between physician and patient perceptions relating to communication and disease management, with patients often having different treatment goals than physicians. Overall, our study suggested that therapies that reduce symptom burden and improve QOL in patients with MPNs are crucial in minimizing disease impact on patient daily lives. Additionally, our findings showed a need for improved patient-physician communication, standardized monitoring of symptoms, and agreement on treatment goals.

Real world epidemiology of myeloproliferative neoplasms: a population based study in Korea 2004-2013

Myeloproliferative neoplasms (MPNs), with an expected increment in number, impose substantial economic and social burdens. To this end, we conducted a nationwide population-based descriptive epidemiology study. We also investigated medical cost associated with MPNs. Prevalence was the highest for essential thrombocythemia (ET) (range 4.1-9.0 per 100,000), followed by polycythemia vera (PV) (range 2.8-5.4 per 100,000) and primary myelofibrosis (PMF) (range 0.5-0.9 per 100,000). ET incurred the highest cumulative total cost at US$35 million and the most frequent hospital visits, while PMF incurred the highest average cost per person at US$5000. The mean hemoglobin level was 16.9 ± 2.2 g/dL for PV males and 15.5 ± 2.7 g/dL for PV females. Further analyses on hemoglobin levels showed the true positive rate of PV from the significantly elevated hemoglobin group (defined as >18.5 g/dL for men and >16.5 g/dL for women) was 3.01% and that of MPNs was 3.1%. Here, we provide the biggest population-based report on MPN epidemiology that can readily be used as a representative Asian data.

Central retinal artery occlusion as a presenting manifestation of polycythaemia vera

A 60-year-old woman with no premorbidities presented with symptoms of sudden painless vision loss in the left eye (LE). Best-corrected visual acuity in the LE was counting fingers close to face. A relative afferent pupillary defect was observed in the LE. Ocular fundus examination of LE was suggestive of central retinal artery occlusion. Systemic evaluation revealed splenomegaly and normal cardiac and carotid arteries. Haematological investigations revealed increased haemoglobin, haematocrit, platelet count and leucocytosis with low erythrocyte sedimentation rate (ESR). Features of myeloproliferative neoplasm were noted on bone marrow aspiration. An assay for JAK2 mutation was positive. Since erythropoietin levels were normal, a diagnosis of primary polycythaemia vera was made and treated with aspirin and phlebotomy twice weekly until the target haematocrit of under 45% was achieved.

Polycythemia vera masked due to severe iron deficiency anemia

Polycythemia vera is one of the chronic myeloproliferative diseases and very few patients present with its actual clinical manifestations. The most common findings are increased red cell mass and an increased leukocyte count with decreased erythropoietin. We present a case where there was a delay in the diagnosis of polycythemia because of menorrhagia in the past. On admission, the patient presented with elevated red and white blood cell counts, erythropoietin was low, and polycythemia was then suspected. A bcr-abl test was performed to rule out chronic myelogenous leukemia. JAK2 mutation was positive, and the patient was diagnosed with polycythemia vera.

Associations between gender, disease features and symptom burden in patients with myeloproliferative neoplasms: an analysis by the MPN QOL International Working Group

The myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis, are distinguished by their debilitating symptom profiles, life-threatening complications and profound impact on quality of life. The role gender plays in the symptomatology of myeloproliferative neoplasms remains under-investigated. In this study we evaluated how gender relates to patients' characteristics, disease complications and overall symptom expression. A total of 2,006 patients (polycythemia vera=711, essential thrombocythemia=830, myelofibrosis=460, unknown=5) were prospectively evaluated, with patients completing the Myeloproliferative Neoplasm-Symptom Assessment Form and Brief Fatigue Inventory Patient Reported Outcome tools. Information on the individual patients' characteristics, disease complications and laboratory data was collected. Consistent with known literature, most female patients were more likely to have essential thrombocythemia (48.6% versus 33.0%; P<0.001) and most male patients were more likely to have polycythemia vera (41.8% versus 30.3%; P<0.001). The rate of thrombocytopenia was higher among males than females (13.9% versus 8.2%; P<0.001) and males also had greater red-blood cell transfusion requirements (7.3% versus 4.9%; P=0.02) with shorter mean disease duration (6.4 versus 7.2 years, P=0.03). Despite there being no statistical differences in risk scores, receipt of most therapies or prior complications (hemorrhage, thrombosis), females had more severe and more frequent symptoms for most individual symptoms, along with overall total symptom score (22.8 versus 20.3; P<0.001). Females had particularly high scores for abdominal-related symptoms (abdominal pain/discomfort) and microvascular symptoms (headache, fatigue, insomnia, concentration difficulties, dizziness; all P<0.01). Despite complaining of more severe symptom burden, females had similar quality of life scores to those of males. The results of this study suggest that gender contributes to the heterogeneity of myeloproliferative neoplasms by influencing phenotypic profiles and symptom expression.

Essential Thrombocythemia and Polycythemia Vera: Focus on Clinical Practice

Bone marrow (BM) morphologic features remain the cornerstone of diagnosis in both essential thrombocythemia (ET) and polycythemia vera (PV). In addition, recently discovered mutations, such as JAK2, CALR, and MPL, have proven useful in facilitating the diagnostic process. A JAK2 mutation is expected in PV, and its absence makes the diagnosis unlikely. However, JAK2 mutations also occur in about 60% of patients with ET, which underlines the need for BM examination in distinguishing JAK2-mutated ET from PV when the hemoglobin/hematocrit level is diagnostically equivocal (ie, as in "masked" PV). Most patients with JAK2-unmutated ET express CALR or MPL mutations, with respective estimated incidences of 22% and 3%, while approxmately 15% are wild-type for all 3 mutations (ie, they are triple-negative). As such, CALR first, followed by MPL if CALR is absent, mutation screening is appropriate in the diagnostic work-up of JAK2-unmutated ET but does not replace the need for BM morphologic examination in (1) confirming the diagnosis in triple-negative ET and (2) distinguishing ET from other myeloproliferative neoplasms that share the same mutations, including masked PV and early/prefibrotic myelofibrosis. Young patients (aged < 60 years) with ET or PV and no history of thrombosis are conventionally regarded as having "low-risk" disease. First-line treatment in low-risk PV is phlebotomy to achieve a hematocrit target of 45% and low-dose aspirin, and first-line treatment in ET is observation alone in the absence of additional risk factors for arterial thrombosis (ie, JAK2 mutation and cardiovascular risk factors) or low-dose aspirin therapy, once or twice daily, in the presence of one or both of these risk factors, respectively. Cytoreductive therapy is indicated in high-risk (patients aged ≥ 60 years or a history of thrombosis) PV or ET in the form of hydroxyurea as first-line and interferon alfa or busulfan as second-line drugs of choice. We do not use ruxolitinib in patients with PV unless they have severe pruritus or symptomatic splenomegaly that is proved to be refractory to hydroxyurea, interferon alfa, and busulfan.

How common are myeloproliferative neoplasms? A systematic review and meta-analysis

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera (PV), essential thrombocythemia (ET), and primary(idiopathic) myelofibrosis (PMF). In this systematic review, we provide a comprehensive report on the incidence and prevalence of MPNs across the globe. Electronic databases (PubMed, EMBASE, MEDLINE, and Web of Science) were searched from their inception to August 2012 for articles reporting MPN incidence or prevalence rates. A random effects meta-analysis was undertaken to produce combined incidence rates for PV, ET, and PMF. Both heterogeneity and small study bias were assessed. Thirty-four studies were included. Reported annual incidence rates ranged from 0.01 to 2.61, 0.21 to 2.27, and 0.22 to 0.99 per 100,000 for PV, ET, and PMF, respectively. The combined annual incidence rates for PV, ET, and PMF were 0.84, 1.03, and 0.47 per 100,000. There was high heterogeneity across disease entities (I(2) 97.1-99.8%) and evidence of publication bias for ET and PMF (Egger test, P = 50.007 and P ≤ 0.001, respectively).The pooled incidence reflects the rarity of MPNs. The calculated pooled incidence rates do not reflect MPN incidence across the globe due to the high unexplained heterogeneity. Improved, widespread registration of MPNs would provide better information for global comparison of the incidence and prevalence of MPNs.

Survival patterns in United States (US) medicare enrollees with non-CML myeloproliferative neoplasms (MPN)

Purpose

Non-CML myeloproliferative neoplasms (MPN) include essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF). Reported median overall survival (OS) ranges from a few to several years for MF, a decade or more for ET and PV. The study objective was to compare US survival rates of ET, PV, and MF patients with matched non-MPN/non-cancer controls in a nationally representative database.

Patients and Methods

Data were taken retrospectively from the Survey, Epidemiology, and End Results (SEER)-Medicare linked database. Medicare enrollees with a new SEER MPN diagnosis between Jan 1, 2001 and Dec 31, 2007 were eligible. First MPN diagnosis was required at or after Medicare enrollment to allow for continuous follow-up. Non-MPN/non-cancer control groups were selected from Medicare separately for each MPN subtype and demographically matched to cases at a ratio of 5∶1. Survival was determined starting from the case diagnosis date using the Kaplan-Meier method.

Results

A total of 3,364 MPN patients (n = 1,217 ET; 1,625 PV; 522 MF) met the inclusion criteria and were matched to controls. Mean age was 78.4, 76.1, and 77.4 years for ET, PV, and MF, respectively, and percent female was 63, 50, and 41. Median OS was significantly (p<0.05) lower for MPN cases vs. controls (ET: 68 vs. 101 months; PV: 65 vs. 104; MF: 24 vs. 106).

Conclusions

In the US Medicare population, survival in MF patients was worse than that of patients with ET or PV and significantly worse than matched controls. Survival of patients with ET or PV was substantially inferior to matched controls. These findings have implications for the clinical management of MPN patients and underscore the need for effective therapies in all MPN subtypes.

Health resource utilization and cost associated with myeloproliferative neoplasms in a large United States health plan

Myelofibrosis (MF), polycythemia vera (PV) and essential thrombocythemia (ET) may lead to bone marrow fibrosis. Because the disease course of ET and PV are long and the disease course of MF may be fatal, healthcare resource utilization (HRU) associated costs of these neoplasms are especially important to understand. We used a large US health insurance claim database to describe the costs of these diseases. Compared to age-gender matched comparisons without myeloproliferative neoplasms (MPN), all aspects of HRU that we examined, including inpatient, outpatient and emergency room visits and pharmacy, as well as overall healthcare expenditures, were significantly higher in patients with MF, PV and ET (e.g. MF total costs = $54 168 vs. $10 203; PV = $14 903 vs. $7913; ET = $29 553 vs. $8026) than in matched comparisons. In order to reduce the burden of illness associated with these diseases, continued efforts in the development of more efficacious treatments for these disorders are needed.

Epidemiology of myelofibrosis, essential thrombocythemia, and polycythemia vera in the European Union

BACKGROUND

Primary myelofibrosis (PMF), essential thrombocythemia (ET), and polycythemia vera (PV) are BCR ABL-negative myeloproliferative neoplasms (MPN). Published epidemiology data are scarce, and multiple sources are needed to assess the disease burden.

METHODS

We assembled the most recent information available on the incidence and prevalence of myelofibrosis (MF), ET, and PV by conducting a structured and exhaustive literature review of the published peer-reviewed literature in EMBASE and by reviewing online documentation from disease registries and relevant health registries in European countries. The search was restricted to human studies written in English or French and published between January 1, 2000, and December 6, 2012.

RESULTS

Eleven articles identified from EMBASE, three online hematology or oncology registries, and two Web-based databases or reports were used to summarize epidemiological estimates for MF, PV, and ET. The incidence rate of MF ranged from 0.1 per 100,000 per year to 1 per 100,000 per year. Among the various registries, the incidence of PV ranged from 0.4 per 100,000 per year to 2.8 per 100,000 per year, while the literature estimated the range of PV incidence to be 0.68 per 100,000 to 2.6 per 100,000 per year. The estimated incidence of ET was between 0.38 per 100,000 per year and 1.7 per 100,000 per year. While a few studies reported on the MPNs' prevalences, it is difficult to compare them as various types of prevalence were calculated (point prevalence vs. period prevalence) and standardization was made according to different populations (e.g., the world population and the European population).

CONCLUSION

There is a wide variation in both prevalence and incidence estimates observed across European data sources. Carefully designed studies, with standardized definitions of MPNs and complete ascertainment of patients including both primary and secondary MFs, should be conducted so that estimates of the population aimed to receive novel treatments for these neoplasms are better understood assist public health planning and provide valuable information about the burden of illness to policy makers, funding agencies, resource planners, healthcare insurers, and pharmaceutical manufacturers.

Chronic myeloproliferative diseases

The chronic myeloproliferative disorders are a group of diseases in which there is an increased proliferation of one or more subtypes of myeloid cells; they include essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). In ET and PV the main neurologic manifestations are headaches, dizziness and macro- and microvascular, both venous and arterial, thrombosis and intracranial hemorrhages. Paresthesias and chorea also occur in PV. In PMF neurologic complications are very rare and consist predominantly of spinal cord compression by extramedullary hematopoiesis tissue.

Could hypoxia increase the prevalence of thrombotic complications in polycythemia vera?

Thromboses represent a major cause of morbidity and mortality in polycythemia vera but the contributing mechanisms are not fully described. To evaluate whether environmental conditions such as altitude/hypoxia could impact thrombosis history, we retrospectively analyzed thrombosis history in 71 polycythemia vera patients living at an elevation of 5000 feet or more in the Salt Lake City (SLC) area and 166 polycythemia vera patients living near sea level in the Baltimore (BLM) area. The SLC cohort was older with a longer disease duration. No significant differences in type of anticoagulation therapy or prothrombotic factors were present between the two cohorts. After adjusting for age, sex and disease duration, SLC patients experienced an estimated 3.9-fold increase in the odds of a history of thrombosis compared with BLM patients (95% confidence interval 1.8-7.6; P=0.0004). A history of a cardiovascular event was present in 58% of the SLC patients compared with 27% of the BLM patients (P<0.0001). Before diagnosis, thrombosis occurred in 18 and 4% of the SLC and BLM groups, respectively (P=0.003). No correlation between the JAK2 allele burden and thrombosis was observed in this study. This retrospective study suggests that even moderate hypoxia associated with 5000 feet elevation should be considered as an independent prothrombotic risk factor. This observation needs to be confirmed by prospective studies.

Antiplatelet drugs for polycythaemia vera and essential thrombocythaemia

BACKGROUND

Polycythaemia vera and essential thrombocythaemia are chronic Philadelphia-negative myeloproliferative neoplasms that increase the risk of arterial and venous thrombosis, as well as bleeding. In addition to the different therapeutic strategies available, an antiplatelet drug is often used to reduce thrombotic risk.

OBJECTIVES

To quantify the benefit and harm of antiplatelet drugs for long-term primary and secondary prophylaxis of arterial and venous thrombotic events in patients with polycythaemia vera or essential thrombocythaemia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library (Issue 1 2012), MEDLINE (1966 to 2012), and EMBASE (1980 to 2012), as well as online registers of ongoing trials and conference proceedings. The date of the last search was October 2012.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing long-term (>6 months) use of an antiplatelet drug versus placebo or no treatment in participants with polycythaemia vera or essential thrombocythaemia, as diagnosed by established international criteria, with data for at least one of the selected outcomes.

DATA COLLECTION AND ANALYSIS

Using a pre-defined extraction form, two review authors independently screened results, extracted data, and assessed quality. We planned to analyse the following outcomes: mortality from arterial and venous thrombotic events (primary efficacy outcome), mortality from bleeding episodes (primary safety outcome), fatal and non-fatal arterial thrombotic events, fatal and non-fatal venous thrombotic events, micro-circulation events, transient neurological and ocular manifestations, major and minor bleeding episodes, and all-cause mortality and any adverse events. We based quantitative analysis of outcome data on an intention-to-treat principle. We used the pooled odds ratio (OR) with 95% confidence interval (CI) with a fixed-effect model (Mantel-Haenszel) to estimate the overall treatment effect.

MAIN RESULTS

We identified no new studies from the updated searches. We included in this review two RCTs for a total of 630 participants. Both RCTs included participants with an established diagnosis of polycythaemia vera and with no clear indication or contraindication to aspirin therapy. We judged both studies to be of moderate quality. Published data from both studies were insufficient for a time-to-event data analysis and for some of the primary and secondary outcomes that we planned. The use of low-dose aspirin, compared with placebo, was associated with a lower risk of fatal thrombotic events (although this benefit was not statistically significant (OR 0.20, 95% CI 0.03 to 1.14; P = 0.07). No data on mortality from bleeding episodes were available. A non-significant benefit of aspirin was shown for all-cause mortality (OR 0.46, 95% CI 0.21 to 1.01; P = 0.05). No increase in the risk of major bleeding was reported in participants taking aspirin compared with those given placebo (OR 0.99, 95% CI 0.23 to 4.36; P = 0.99), and a non-significant increase with aspirin treatment was shown for minor bleeding (OR 1.85, 95% CI 0.90 to 3.79; P = 0.09). No published studies have reported findings in participants with essential thrombocythaemia or in the study of other antiplatelet drugs.

AUTHORS' CONCLUSIONS

For patients with polycythaemia vera who have no clear indication or contraindication to aspirin therapy, available evidence suggests that the use of low-dose aspirin, when compared with no treatment, is associated with a statistically non-significant reduction in the risk of fatal thrombotic events and all-cause mortality, without an increased risk of major bleeding.

When the Brakes are Lost: LNK Dysfunction in Mice, Men, and Myeloproliferative Neoplasms

Aberrant JAK-STAT signaling is a hallmark of myeloproliferative neoplasms (MPNs). These hyperproliferative disorders are classically associated with activating mutations in tyrosine kinases such as JAK2 and the thrombopoietin (TPO) receptor MPL. Activation of JAK-STAT signaling and responses to JAK2 inhibitors have been observed in MPN patients lacking JAK2 or MPL mutations, suggesting that other regulatory elements in the JAK-STAT pathway are altered. However, the molecular basis for this observation has been unclear. Recently, the role of inhibitory regulators of JAK-STAT signaling in MPN pathogenesis has been increasingly recognized. LNK is an adaptor protein that forms a negative feedback loop by binding to MPL and JAK2 and inhibiting downstream STAT activation. Murine models indicate that loss of LNK function can promote the development of a MPN phenotype. Several recent studies have identified novel LNK mutations in MPNs, thus validating this notion in humans. These findings represent a novel genetic paradigm of loss of negative feedback regulation of JAK-STAT activation in MPNs and have implications for the future development of targeted therapies in MPNs.

Patterns of survival among patients with myeloproliferative neoplasms diagnosed in Sweden from 1973 to 2008: a population-based study

PURPOSE

Reported survival in patients with myeloproliferative neoplasms (MPNs) shows great variation. Patients with primary myelofibrosis (PMF) have substantially reduced life expectancy, whereas patients with polycythemia vera (PV) and essential thrombocythemia (ET) have moderately reduced survival in most, but not all, studies. We conducted a large population-based study to establish patterns of survival in more than 9,000 patients with MPNs.

PATIENTS AND METHODS

We identified 9,384 patients with MPNs (from the Swedish Cancer Register) diagnosed from 1973 to 2008 (divided into four calendar periods) with follow-up to 2009. Relative survival ratios (RSRs) and excess mortality rate ratios were computed as measures of survival.

RESULTS

Patient survival was considerably lower in all MPN subtypes compared with expected survival in the general population, reflected in 10-year RSRs of 0.64 (95% CI, 0.62 to 0.67) in patients with PV, 0.68 (95% CI, 0.64 to 0.71) in those with ET, and 0.21 (95% CI, 0.18 to 0.25) in those with PMF. Excess mortality was observed in patients with any MPN subtype during all four calendar periods (P < .001). Survival improved significantly over time (P < .001); however, the improvement was less pronounced after the year 2000 and was confined to patients with PV and ET.

CONCLUSION

We found patients with any MPN subtype to have significantly reduced life expectancy compared with the general population. The improvement over time is most likely explained by better overall clinical management of patients with MPN. The decreased life expectancy even in the most recent calendar period emphasizes the need for new treatment options for these patients.

Pathology consultation on myeloproliferative neoplasms

In 2008, the World Health Organization (WHO) revised the classification system for myeloproliferative neoplasms (MPNs). MPNs include chronic myelogenous leukemia, essential thrombocythemia, polycythemia vera, primary myelofibrosis, and several other disorders. The newer classification system incorporates mutations discovered in the JAK2 and MPL genes. The importance of understanding the role of mutations in JAK2, MPL, and other genes that have been discovered in MPNs is highlighted by the change in the 2008 WHO MPN classification system. Moreover, the development of highly specific inhibitors of JAK2 further stresses the importance of molecular testing in MPN diagnosis and prognosis.

Relationship between clotting activity and phosphatidylserine expression on erythrocyte membranes in polycythemia vera patients with the JAK2 V617F mutation

INTRODUCTION

Polycythemia vera (PV) accompanies the clinical course of thrombosis. Phosphatidylserine (PS) expression on the plasma membrane has been known to be one of place where the coagulation system activates. We studied the relationship between clotting factor activity and PS expression on the erythrocyte membrane in patients with erythrocytosis.

METHODS

The coagulation test and PS expression in 23 patients with erythrocytosis were measured. PS expression was determined indirectly by measuring annexin V binding to erythrocytes using fluorescence activated cell sorter analysis (FACS).

RESULTS

The activity of clotting factors (II, V, VII, VIII, von Willebrand factor, IX, X) was significantly lower in PV than in the mutation-negative erythrocytosis. There was a significant correlation between reduced activity of clotting factors such as V, X, and IX and increased PS expression of the erythrocyte membrane.

CONCLUSION

Increased expression of PS on the erythrocyte membrane may reduce the activities of clotting factors in PV patients with JAK2 V617F mutation.

Myeloproliferative neoplasms cause glomerulopathy

Myeloproliferative neoplasms are clonal hematopoietic stem cell disorders that can produce an undefined glomerulopathy. To better characterize the glomerular disease associated with myeloproliferative neoplasms, we evaluated features of 11 patients with myeloproliferative neoplasm-related glomerulopathy that included 8 patients with primary myelofibrosis, and 1 each with chronic myelogenous leukemia, polycythemia vera, and essential thrombocythemia. Indications for biopsy were nephrotic-range proteinuria (nephrotic syndrome in four) and chronic renal insufficiency. The mean time from diagnosis of the neoplasms to biopsy was 7.2 years. Histologically, mesangial sclerosis and hypercellularity were seen in all 11 cases, segmental sclerosis in 8, features of chronic thrombotic microangiopathy in 9, and intracapillary hematopoietic cells in 4. On follow-up, seven patients had persistent renal dysfunction and four progressed to end-stage renal disease (ESRD). Thus, glomerulopathy appears to be a late complication of myeloproliferative neoplasms, particularly primary myelofibrosis, with guarded prognosis. Greater awareness of this entity and larger studies are needed to define possible therapies.

JAK2 V617F and beyond: role of genetics and aberrant signaling in the pathogenesis of myeloproliferative neoplasms

Dysregulated signaling is a hallmark of chronic myeloproliferative neoplasms (MPNs), as evidenced by the identification of the activating JAK2 V617F somatic mutation in almost all patients with polycythemia vera (PV) and 50-60% of essential thrombocythemia and primary myelofibrosis patients. These disorders are clinically distinct, raising the question of how a single mutation can result in such phenotypic diversity. Mouse models have demonstrated that the level of JAK2 V617F expression can modulate the phenotype, and clinical studies of JAK2 V617F allele burden have reported similar findings. It has also been hypothesized that one or more pre-JAK2 V617F events may modify the MPN phenotype. However, the molecular basis of JAK2 V617F-negative essential thrombocythemia and primary myelofibrosis remains largely unexplained. Mutations in the TET2 gene have been identified in both JAK2 V617F-positive and -negative MPNs and other myeloid neoplasms, but their functional and clinical significance have yet to be clarified. In addition, recent reports have identified a specific germline haplotype that increases the predisposition to MPNs. The role of inhibitory pathways (e.g., SOCS and LNK) in regulating JAK-STAT signaling in MPNs is being increasingly recognized. The implications of these findings and their clinical relevance are the focus of this article.

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.

Use of molecular testing to identify a cluster of patients with polycythemia vera in eastern Pennsylvania

BACKGROUND

The role of the environment in the origin of polycythemia vera has not been well documented. Recently, molecular diagnostic tools have been developed to facilitate the diagnosis of polycythemia vera. A cluster of patients with polycythemia vera was suspected in three countries in eastern Pennsylvania where there have long been a concern about environment hazards.

METHODS

Rigorous clinical criteria and JAK2 617V>F testing were used to confirm the diagnosis of polycythemia vera in patients in this area. Participants included cases of polycythemia vera from the 2001 to 2005 state cancer registry as well as self- and physician-referred cases.

FINDING

A diagnosis of polycythemia vera was confirmed in 53% of 62 participants using WHO criteria, which includes JAK2 617V>F testing. A statistically significant cluster of cases (P < 0.001) was identified where the incidence of polycythemia vera was 4.3 times that of the rest of the study area. The area of the cluster contained numerous sources of hazardous material including waste-coal power plants and U.S. Environmental Protection Agency Superfund sites.

INTERPRETATION

The diagnosis of polycythemia vera based solely on clinical criteria is frequently erroneous, suggesting that our prior knowledge of the epidemiology of this disease might be inaccurate. The JAK2 617V>F mutational analysis provides diagnostic clarity and permitted the confirmation of a cluster of polycythemia vera cases not identified by traditional clinical and pathologic diagnostic criteria. The close proximity of this cluster to known areas of hazardous material exposure raises concern that such environmental factors might play a role in the origin of polycythemia vera.

New and old prognostic factors in polycythemia vera

Polycythemia vera is a chronic myeloproliferative disorder affecting people in the sixth decade of life. The disease is considered long-lasting; median survival exceeds 18 years. As thrombosis is the main complication during follow-up, scoring systems have focused on the risk of thrombosis. Age over 60 years and prior thrombosis are considered the standard risk factors for thrombosis and represent the state of the art for risk stratification in decision making regarding treatment. However, new disease-based risk factors-leukocytosis and the JAK2V617F mutation burden-seem to be emerging as indicators of prognosis in polycythemia vera. Leukocytosis, as a marker of disease proliferation, seems to have an impact on thrombosis, post-polycythemia vera myelofibrosis, leukemia, and survival. The role of the JAK2V617F mutation as a prognostic factor requires further validation, but it may have a dominant role in disease progression and in the activation of platelets and leukocytes.

Antiplatelet drugs for polycythaemia vera and essential thrombocythaemia

BACKGROUND

Polycythaemia vera and essential thrombocythaemia are chronic Philadelphia-negative myeloproliferative disorders, which increase the risk of arterial and venous thrombosis as well as bleeding. In addition to the different therapeutic strategies available, aspirin is often used to prevent platelet aggregation.

OBJECTIVES

To quantify the benefit and harm of antiplatelet drugs for long-term primary and secondary prophylaxis of arterial and venous thrombotic events in patients with polycythaemia vera or essential thrombocythaemia.

SEARCH STRATEGY

Our searched included the CENTRAL (The Cochrane Library, issue 1 2007), MEDLINE (1966 to 2007) and EMBASE (1980 to 2007) databases, online registers of ongoing trials and conference proceedings. The date of the last search was March 2007.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing long-term (>6 months) use of an antiplatelet drug versus placebo or no treatment in patients with polycythaemia vera or essential thrombocythaemia, diagnosed by established international criteria, with data for at least one of the selected outcomes, were included.

DATA COLLECTION AND ANALYSIS

Using a predefined extraction form, we collected and analysed the following data where appropriate: mortality from arterial and venous thrombotic events, mortality from bleeding episodes, fatal and non-fatal arterial thrombotic events, fatal and non-fatal venous thrombotic events, micro-circulation events, transient neurological and ocular manifestations, major and minor bleeding episodes, all-cause mortality and any adverse events. We based quantitative analysis of outcome data on an intention-to-treat principle. The overall treatment effect was estimated by the pooled odds ratio (OR) with 95% confidence interval (CI) using a fixed-effect model (Mantel-Haenszel).

MAIN RESULTS

Two RCTs that investigated 630 patients with an established diagnosis of polycythaemia vera, with no clear indication or contraindication to aspirin therapy, were included in this review. The use of aspirin, compared with placebo, was associated with a lower risk of fatal thrombotic events (although this benefit was not statistically significant (OR 0.20, 95% CI 0.03 to 1.14)) and did not increase the risk of major bleeding (OR 0.99, 95% CI 0.23 to 4.36). No studies have been published in patients with essential thrombocythaemia or studying other antiplatelet drugs.

AUTHORS' CONCLUSIONS

The available evidence suggests that the use of aspirin is associated with a statistically non-significant reduction in the risk of fatal thrombotic events, without an increased risk of major bleeding, when compared with no treatment in patients polycythaemia vera who have no clear indication or contraindication to aspirin therapy.

Life expectancy and prognostic factors in the classic BCR/ABL-negative myeloproliferative disorders

Among the 'classic' BCR/ABL-negative chronic myeloproliferative disorders, primary myelofibrosis (PMF) is associated with a substantial life-expectancy reduction. In this disease, initial haemoglobin level is the most important prognostic factor, whereas age, constitutional symptoms, low or high leukocyte counts, blood blast cells and cytogenetic abnormalities are also of value. Several prognostic systems have been proposed to identify subgroups of patients with a different risk, which is especially important in younger individuals, who may benefit from therapies with curative potential. Essential thrombocythaemia (ET) affects the patients' quality of life more than the survival, due to the high occurrence of thrombosis, whereas polycythaemia vera (PV) has a substantial morbidity derived from thrombosis but also a certain reduction in life expectancy. Therefore, in the latter disorders, prognostic studies have focused primarily on prediction of the thrombosis, with age and a previous history of thrombosis being the main prognostic factors of such complication. The importance of higher leukocyte counts in thrombosis development has been recently pointed out in ET and PV, where a role for mutated JAK2 allele burden has also been noted. With regard to PMF, the possible association of the mutation with shorter survival and higher acute transformation rate is currently being evaluated.

Geriatric Chorea

The differential diagnosis, diagnostic evaluation, and treatment of late-onset chorea are reviewed. Late-onset chorea is rare and has a heterogeneous causation. A systematic approach to geriatric chorea greatly enhances a correct diagnosis. An accurate diagnosis is important because many causes of chorea are treatable or or, when heritable, may have significant implications for subsequent generations. Most late-onset chorea is either nonlimiting, requiring no treatment, has a spontaneous remission, or responds to medication. In a minority of patients, chorea is medically refractory or manifestation of an untreatable disorder.

Life expectancy and prognostic factors for survival in patients with polycythemia vera and essential thrombocythemia

PURPOSE

To assess life expectancy and prognostic factors for survival in patients with polycythemia vera and essential thrombocythemia.

METHODS

The study sample consisted of 831 consecutive patients with polycythemia vera (n = 396; 4184 person-years of follow-up) or essential thrombocythemia (n = 435; 4304 person-years of follow-up). Mortality in each group was compared with the Italian population using the standardized mortality ratio (SMR) based on life expectancy data obtained from the Italian Institute of Statistics.

RESULTS

The 15-year survival was 65% in patients with polycythemia and 73% in those with thrombocythemia. By Cox regression analysis, the independent predictors of death were a history of thrombosis for polycythemia (hazard ratio [HR] = 2.2; P = 0.0002) and thrombocythemia (HR = 2; P = 0.01), and male sex (HR = 1.8; P = 0.03) for thrombocythemia. Mortality compared with the general population was 1.6-fold higher (P <0.001) in patients with polycythemia but was not increased in those with thrombocythemia (SMR = 1; P = 0.8).

CONCLUSION

Life expectancy of patients with polycythemia vera (especially if younger than 50 years) was reduced compared with the general population, whereas life expectancy of patients with essential thrombocythemia was not affected significantly by the disease, reflecting the more indolent nature of the proliferation. History of thrombosis was the main predictor of death in both diseases.

Trends in the incidence of chronic Philadelphia chromosome negative (Ph-) myeloproliferative disorders in the city of Göteborg, Sweden, during 1983-99

OBJECTIVE

In the literature the incidence rates for the chronic Philadelphia chromosome negative (Ph-) myeloproliferative disorders (MPD) are known to vary extensively; only a few studies have, however, been concerned with incidence trends over time. Therefore, the aim of the present work was to investigate possible trends as regards incidence rates over time for Ph-MPD.

DESIGN

Herein, we carried out a retrospective population-based survey on the incidence of polycythaemia vera (PV), essential thrombocythaemia (ET) and chronic idiopathic myelofibrosis (IMF), in the city of Göteborg (Sweden), covering the years 1983-99.

RESULTS

The study comprised 416 patients with Ph-MPD. There were 205 patients with PV, 153 patients with ET, 34 with IMF and 24 with unclassified MPD. The annual incidence for PV was 1.97 per 10(5) inhabitants; the corresponding figures for ET and IMF were 1.55 per 10(5) and 0.30 per 10(5) inhabitants, respectively. There was a significant increase in the annual incidence rate for ET (P = 0.008); this increase was significant for male subjects (P = 0.015) but did not reach significance for females (P = 0.118). No such increase over time was recorded as regards PV and IMF.

CONCLUSIONS

The increasing annual incidence rate for ET is most possibly explained by the more frequent use of automated platelet counts whenever a patient consults a doctor. Thereby, an increasing number of patients with overt thrombocytosis of unknown origin are discovered and will be referred to specialists within the field of haematology for a correct diagnosis.

Polycythemia and oxygen sensing

Polycythemias can be differentiated based on the responsiveness of erythroid progenitors to circulating cytokines. Primary polycythemias are characterized by an augmented response due to acquired somatic or inherited germ-line mutations that are expressed within hematopoietic progenitors causing increased proliferation or decreased apoptosis and resulting in accumulation of red blood cells. In terms of oxygen requirements, primary polycythemias can be viewed as the production of hemoglobin fully dissociated from the tissue oxygen needs and from the oxygen sensing pathway. Polycythemia vera (PV) is the most common primary polycythemia. PV bone marrow progenitors cells can form erythroid colonies in the absence of exogenous erythropoietin in vitro. These endogenous erythroid colonies (EEC) are useful in differentiating PV and secondary polycythemias. They also can differentiate PV where this feature is independent of Epo signalling from primary familial and congenital polycythemia. In this autosomal dominant primary polycythemia, at variance with PV, EEC formation is abolished by anti-Epo and anti-Epo receptor neutralising antibodies. Mutations of the EPOR have been described and resulted in nine cases in truncated EPORs lacking the cytoplasmic carboxy-terminal of the receptor which possesses a negative growth regulatory domain. However, recent data suggest that different mutations may cause PFCP in most cases. Secondary polycythemia can be viewed as either physiological response to satisfy the oxygen needs of the tissues, resulting for instance from high affinity hemoglobins or BPG mutase deficiency, or as the result of germ-line or somatic mutations disturbing the oxygen sensing pathway or its target: Epo. Chuvash polycythemia is a frequently symptomatic disorder with an autosomal recessive inheritance and inappropriately high Epo levels. The erythroid progenitors are hypersensitive to Epo linking this condition to both primary and secondary polycythemia. A germline missense mutation at nucleotide 598 in both alleles of the von Hippel-Lindau gene results in increased hypoxia inducible factor-1 (HIF-1) expression in normoxic conditions. HIF-1 controls the expression of many genes including Epo. Identifying causal defects in other situations like post-renal transplant erythrocytosis and cases of autosomal dominant polycythemia with high Epo levels will help further understanding of the regulation of erythropoiesis.

Classification and molecular biology of polycythemias (erythrocytoses) and thrombocytosis

In this article, polycythemic disorders are classified based on the current understanding of biology of erythropoieses and divided into primary and secondary polycythemias. Special emphasis is given to recently uncovered molecular bases of newly described congenital polycythemic disorders. This clarification of the pathophysiology of some of the congenital polycythemic states has obvious utility for more accurate diagnosis and rational prognostic determination. The molecular basis of congenital thrombocytoses is only beginning to be uncovered. In contrast, the molecular bases of polycythemia vera and essential thrombocythemia remain unknown, thus their diagnostic criteria are imprecise and their treatment remains largely empirical. The central premise of this article is that deciphering the molecular basis of human diseases leads to improved understanding of hematopoiesis, precise diagnosis, and the potential for development of a specific therapy.

Polycythemia vera: a comprehensive review and clinical recommendations

More than a century has elapsed since the appearance of the modern descriptions of polycythemia vera (PV). During this time, much has been learned regarding disease pathogenesis and PV-associated molecular aberrations. New information has allowed amendments to traditional diagnostic criteria. Phlebotomy remains the cornerstone treatment of PV, whereas myelosuppressive agents may augment the benefit of using phlebotomy for thrombosis prevention in high-risk patients. Excessive aspirin use is contraindicated in PV, although the use of lower-dose aspirin has been shown to be safe and effective in alleviating microvascular symptoms including erythromelalgia and headaches. Recent studies have shown the utility of selective serotonin receptor antagonists for treating PV-associated pruritus. Nevertheless, many questions remain unanswered. What is the specific genetic mutation or altered molecular pathway that is causally related to the disease? In the absence of a specific molecular marker, how is a working diagnosis of PV made? What evidence supports current practice in the management of PV? This article summarizes both old and new information on PV; proposes a modern diagnostic algorithm to formulate a working diagnosis; and provides recommendations for patient management, relying whenever possible on an evidence-based approach.

Clinical and scientific advances in the Philadelphia-chromosome negative chronic myeloproliferative disorders

The chronic myeloproliferative disorders are clonal hematopoietic stem cell disorders and include chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and agnogenic myeloid metaplasia (AMM). These diseases are characterized by clonal expansion of the myeloid compartment, increased marrow angiogenesis, and varying risks for blastic transformation. A clear molecular abnormality exists (t(9;22) leading to the fusion of BCR-Abl) only for CML, which led to effective targeted therapy (STI-571). Since no similar pathogenetic mechanism has been discovered for the t(9;22) negative chronic myeloproliferative disorders, their respective diagnosis is currently based on a variety of rather cumbersome diagnostic criteria. Polycythemia vera is distinguished from reactive erythrocytosis through erythropoietin independent growth of erythroid progenitors in vitro, suppressed levels of endogenous erythropoietin, possible overexpression of PRV-1 (polycythemia rubra vera-1), decreased c-Mpl expression on megakaryocytes, as well as overexpression of bcl-xL, and potentially aberrant activity of the Jak-Stat pathway. ET is defined by thrombocytosis and is distinguished from reactive states by decreased megakaryocyte c-Mpl expression, and a propensity for thrombosis. AMM has been associated with a variety of observations including increased concentrations of pro-fibrotic cytokines, increased angiogenesis, and myeloid expansion. AMM is often indistinguishable clinically and prognostically from the advanced phases of other CMPD (specifically post-polycythemic and post-thrombocythemia myeloid metaplasia), all of which are subentities of a diagnosis of myelofibrosis with myeloid metaplasia (MMM). The management of CMPD patients is quite varied given the broad range of disease severity and survival observed. The role of stem cell transplantation is limited by the age and comorbidities encountered in CMPD patients. Since no broadly applicable therapy effects the mortality of the CMPD, management currently focuses on the prevention/palliation of disease morbidity (i.e. vascular complications, pruritus, organomegaly, constitutional symptoms). Palliative strategies which currently focus on non-specific myelosuppresion, will hopefully be soon replaced by targeted therapies as insight into pathogenetic mechanisms of these diseases evolves.

Peripheral blood findings in chronic myeloproliferative disorders

Chronic myeloproliferative disorders are now frequently detected on routine total blood count. A careful analysis of PB smears allows the diagnosis in many cases, and helps to classify most of them. The peripheral blood parameters may be of prognostic value, especially in AMM. During the follow-up of CMPD, modifications of the PB are of great interest to detect an evolution toward a myelofibrosis or a blastic phase.

Current management of polycythemia vera

Over a century has elapsed since the first description of polycythemia vera (PV), and current treatment recommendations are primarily based on the results of clinical trials that were performed in the late 1960s and early 1970s. Continued identification and appropriate utilization of PV-specific biologic parameters may allow substantial modification of early diagnostic criteria. New cytoreductive treatment agents are increasingly being used without any evidence of superiority over conventional therapy. The role of aspirin is being readdressed by an ongoing controlled study. Transformation of PV into either myelofibrosis with myeloid metaplasia or acute leukemia remains a major complication that may not be influenced by current therapy.