Real-world status of treatment for lymphoid neoplasms developed during the course of myeloproliferative neoplasms in Japan

OBJECTIVES

Patients with myeloproliferative neoplasms (MPNs) are at higher risk of developing secondary malignancies. In this study, we focused on patients with MPNs that complicated lymphoid neoplasms. To analyze the real-world status of lymphoid neoplasm treatment in patients with pre-existing MPNs in Japan, we conducted a multicenter retrospective study.

METHODS

Questionnaires were sent to collect the data on patients who were first diagnosed with either polycythemia vera, essential thrombocythemia or myelofibrosis and who later were complicated with lymphoid neoplasms defined as malignant lymphoma, multiple myeloma, or chronic lymphocytic leukemia/small cell lymphoma.

RESULTS

Twenty-four patients with MPNs complicated by lymphoid neoplasms were enrolled (polycythemia vera, n = 8; essential thrombocythemia, n = 14; and primary myelofibrosis, n = 2). Among these, diffuse large B-cell lymphoma (DLBCL) was the most frequently observed (n = 13, 54.1%). Twelve (92.3%) of the patients with DLBCL received conventional chemotherapy. Among these 12 patients, regarding cytoreductive therapy for MPNs, 8 patients stopped treatment, one continued treatment, and two received a reduced dose. Consequently, most patients were able to receive conventional chemotherapy for DLBCL with a slightly higher dose of granulocyte colony-stimulating factor support than usual without worse outcomes. All 3 patients with multiple myeloma received a standard dose of chemotherapy.

CONCLUSION

Our data indicate that if aggressive lymphoid neoplasms develop during the course of treatment in patients with MPNs, it is acceptable to prioritize chemotherapy for lymphoma.

Thromboembolic events, major bleeding and mortality in essential thrombocythaemia and polycythaemia vera-A matched nationwide population-based study

Thromboembolic events and bleeding are known complications in essential thrombocythaemia (ET) and polycythaemia vera (PV). Using multiple Swedish health care registers, we assessed the rate of arterial and venous events, major bleeding, all-cause stroke and all-cause mortality in ET and PV compared to matched controls. For each patient with ET (n = 3141) and PV (n = 2604), five matched controls were randomly selected. In total, 327 and 405 arterial or venous events were seen in the group of ET and PV patients respectively. Compared to corresponding controls, the rate of venous thromboembolism, major bleeding and all-cause mortality per 100 treatment years was significantly increased among both ET (0.63, 0.79 and 3.70) and PV patients (0.94, 1.20 and 4.80). The PV patients also displayed a significantly higher rate of arterial events and all-cause stroke compared to controls. When dividing the cohort into age groups, we found a significantly higher rate of arterial and venous events in all age groups of PV patients, and the rate of all-cause mortality was significantly higher in both ET and PV patients in all ages above the age of 50. This study confirms that PV and ET are diseases truly marked by thromboembolic complications and bleeding.

Neutrophil-to-lymphocyte ratio and all-cause mortality with and without myeloproliferative neoplasms-a Danish longitudinal study

The neutrophil-to-lymphocyte ratio(NLR) is increased in chronic inflammation and myeloproliferative neoplasms (MPN). We hypothesize that NLR is associated with all-cause mortality and mortality by comorbidity burden in the general population and individuals with MPN. We included 835,430 individuals from The Danish General Suburban Population Study, general practitioners, and outpatient clinics. We investigated NLR on mortality stratified by prevalent and incident MPN, essential thrombocythemia (ET), polycythemia vera (PV), myelofibrosis (MF), comorbidity burden (CCI-score), and the Triple-A risk score using hazard ratio (HR) and 95% confidence interval (95%CI). NLR 1-1.9 was the reference level. During a median follow-up of 11.2 years, 197,802 deaths were recorded. All-cause mortality increased for a stepwise increasing NLR with a HR (95%CI) for NLR ≥ 6 of 2.06(2.03-2.09) for the whole population and 2.93(2.44-3.50) in prevalent MPN. ET, PV, and MF had a HR (95%CI) for NLR ≥ 2 of 2.14(1.71-2.69), 2.19(1.89-2.54), and 2.31(1.91-2.80). Results were similar for incident MPN. Mortality was higher for stepwise increasing NLR and CCI-score(pinteraction < 2×10-16), with a HR for NLR ≥ 6 of 2.23(2.17-2.29), 4.10(4.01-4.20), and 7.69(7.50-7.89), for CCI-score 0, 1-2, or ≥3. The Triple-A risk score demonstrated alignment with NLR. Increasing NLR and comorbidity burden were associated with lower survival in individuals without MPN but were even worse in prevalent and incident MPN, ET, PV, and MF.

Prevalence of frailty and its association with clinical outcomes in myeloproliferative neoplasms: a population-based study

Clinical implications of frailty in myeloproliferative neoplasms (MPN), including essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF), are unknown. In this population-based study, all incident cases of MPN from the Ontario cancer registry between 2004 and 2019 (N = 10 336; ET = 5108; PV = 3843; MF = 1385) and their matched controls (for age, sex, residence, and income) in a 1:4 ratio were included. Baseline frailty measured using the Johns Hopkins Adjusted Clinical Groups frailty indicator and McIsaac frailty index (mFI), categorized as fit, prefrail, or frail if mFI <0.10, 0.11 to 0.20, >0.20), was significantly higher in ET, PV, and MF compared with matched controls (standardized mean difference of 0.27, 0.27, and 0.28). Over 23%, 20%, and 34% of patients with ET, PV, and MF were frail or prefrail despite a younger age (<65 years) or minimal comorbidities. In Cox proportional regression, frailty was independently associated with worse overall survival (OS) after adjusting for age, sex, and comorbidities compared with mFI-fit patients. The hazard ratios (95% confidence interval) for OS for mFI-prefrail and mFI-frail patients were: 1.6 (1.3-1.9) and 3.6 (2.9-4.4) in ET, 1.3 (1.1-1.5) and 2.7 (2.1-3.4) in PV, and 1.2 (1.0-1.5) and 2.0 (1.5-2.7) in MF. Patients with MPN have a substantially higher prevalence of frailty compared with matched controls, which is associated with reduced OS, independent of age or comorbidities.

Statin use, survival and incidence of thrombosis among older patients with polycythemia vera and essential thrombocythemia

BACKGROUND

Polycythemia vera (PV) and essential thrombocythemia (ET) are linked to increased risk of cardiovascular morbidity and mortality. In addition to the reduction in of arterial thrombotic events, statins may prevent venous thrombosis including among patients with cancer. As previous registry- and claims-based studies revealed that the use of statins may improve the survival of patients with various malignancies we evaluated their impact on outcomes of older adults with PV and ET.

METHODS

We identified 4010 older adults (aged 66-99 years at diagnosis) with PV (n = 1809) and ET (n = 2201) in a population-based cohort study using the Surveillance, Epidemiology, and End Results-Medicare database with median follow-up of 3.92 (interquartile range: 2.58-5.75) years. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) approaches were utilized to assess potential association between statins and overall survival. Multivariable competing risk models with death as a competing risk were used to evaluate possible relationship between statins and the incidence of thrombosis.

RESULTS

55.8% of the patients used statins within the first year after PV/ET diagnosis, and statin use was associated with a 22% reduction in all-cause mortality (PSM: hazard ratio [HR] = 0.78, 95% confidence interval [CI]: 0.63-0.98, p = 0.03; IPTW: HR = 0.79, 95% CI: 0.64-0.97, p = 0.03). Statins also reduced the risk of thrombosis in this patient population (PSM: HR = 0.63, 95% CI: 0.51-0.78, p < 0.01; IPTW: HR = 0.57, 95% CI: 0.49-0.66, p < 0.01) as well as in PV and ET subgroups.

CONCLUSIONS

These findings suggest that it may be important to incorporate statins into the therapeutic strategy for older adults with PV and ET.

Characterization of myeloproliferative neoplasms in the paediatric and young adult population

The aim of this study was to compare the genomic features and clinical outcomes between paediatric and young adult patients (PAYA, <40 years) and older adults (OA, ≥40 years) with myeloproliferative neoplasms (MPN) to gain insight into pathogenesis, disease prognosis and management. Of 630 MPN patients, 171 (27%) were PAYA with an average age at diagnosis of 31 years. Females were more prevalent in PAYA than OA (71% vs 58%; p = 0.002), and PAYA more frequently presented with essential thrombocytosis (ET) at diagnosis (67% vs 39%; p < 0.001). The presence of a JAK2 somatic mutation was higher in OA (80.4% vs 64.3%; p < 0.001), while a CALR mutation or lack of any traditional driver mutation was more common in PAYA (20.5% vs 10.5%; p = 0.001, 8.8% vs 3.7%; p = 0.01 respectively). Venous thrombosis was more common in PAYA compared to OA (19.8% vs 10.7%; p = 0.002). PAYA had a higher prevalence of familial MPN and familial cancer predisposition, and two PAYA patients harboured pathogenic germline JAK2 lesions. PAYA demonstrated longer survival from diagnosis than OA (median not reached vs 13 years), while disease transformation was less frequent (19.3% vs 37.9%).

Splenic Infarction in Patients with Philadelphia-negative Myeloproliferative Neoplasms

Objective We retrospectively analyzed the prevalence and clinical features of splenic infarctions in patients with Philadelphia chromosome-negative myeloproliferative neoplasms (Ph^- MPNs). Patients Patients diagnosed with essential thrombocythemia (ET), polycythemia vera (PV), prefibrotic/early primary myelofibrosis (pre-PMF), or PMF from January 1996 to October 2020 in Chungnam National University Hospital, Daejeon, Korea, were reviewed. Results A total of 347 patients (143 ET, 129 PV, 44 pre-PMF, and 31 PMF patients; 201 men and 146 women) with a median age of 64 (range 15-91) years old were followed up for a median of 4.7 (range 0.1-26.5) years. Fifteen (4.3%) patients exhibited splenic infarctions at the diagnosis. These were most common in PMF patients (12.9%), followed by pre-PMF (9.1%) and PV (5.4%) patients. Multifocal infarcts (60.0%) were most common, followed by solitary (33.3%) and extensive infarcts (6.7%). The cumulative incidence of thrombosis in patients with splenic infarctions tended to be higher than in those lacking infarctions (10-year incidence 46.7% vs. 21.0% in PV; p=0.215; 33.3% vs. 17.9% in pre-PMF; p=0.473) patients, but statistical significance was lacking. Palpable splenomegaly (hazard ratio 14.89; 95% confidence interval 4.00-55.35; p<0.001) was the only independent risk factor for splenic infarction. During follow-up, 5 (1.4%) patients developed splenic infarctions. Conservative treatment adequately controlled the symptoms; no serious complications were noted in any patient. Conclusion Splenic infarctions occurred most frequently in patients with PMF; it was rare in patients with ET. The clinical courses were generally mild.

Neutrophil-lymphocyte ratio and carotid plaque burden in patients with essential thrombocythemia and polycythemia vera

BACKGROUND AND AIMS

Chronic inflammation plays a critical role in the pathogenesis of myeloproliferative neoplasm (MPN), and inflammatory conditions are closely related to the development and exacerbation of atherosclerosis. This study aimed to compare carotid plaque burden and neutrophil-lymphocyte ratio (NLR) in the essential thrombocythemia (ET)/polycythemia vera (PV) and control groups.

METHODS AND RESULTS

We retrospectively assessed carotid plaque burden and NLR in patients with ET/PV between January 2010 and September 2021 and propensity-score matched these patients to control subjects from the general population. All patients underwent carotid imaging using carotid ultrasonography for atherosclerosis screening. After 3:1 propensity-score matching, 140 patients in the control group were matched to 51 patients in ET/PV group. The mean NLR was significantly higher in the MPN group than in the control group (4.77 ± 3.96 vs. 1.93 ± 1.03, p < 0.001). The carotid plaque score was also higher in MPN group than in the control group (2.37 ± 1.47 vs. 1.94 ± 1.17, p = 0.038).

CONCLUSION

Patients with PV/ET show a higher NLR and carotid plaque burden than the normal population. This reflected that PV/ET was a highly inflammatory and atherosclerotic condition expressing potentially increased cardiovascular risk.

Essential Thrombocythemia among Patients with Myeloproliferative Neoplasms in Haematology Unit of a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction: Essential thrombocythemia, a myeloproliferative condition with an increased number of circulating platelets, is a rare hematological malignancy. The aim of the study is to find out the prevalence of essential thrombocythemia among patients with myeloproliferative neoplasms presenting in haematology unit of a tertiary care centre. Methods: This was a descriptive cross-sectional study at a tertiary care centre from September, 2020 to September, 2021 (Reference number: 48 (6-11) E2077/076). All the patients with a diagnosis of essential thrombocythemia and willing to give consent were included in the study while the patients with incomplete investigations were excluded. A sample size of 72 patients was taken and convenience sampling was done. Data were entered in Microsoft Excel 2010 and analysis was done by the Statistical Package for the Social Sciences Version 22.0. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data along with mean and standard deviation for continuous data. Results: Among 72 patients with myeloproliferative neoplasms, the prevalence of essential thrombocythemia was found to be 17 (23.61%) (13.80-33.42 at a 95% Confidence Interval). The mean age of patients was 55.41±11.20 years with a male to female ratio of 9:8. The mean hemoglobin level and platelet count in patients were found to be 11.20±2.1 g/dl and 677000±262067.70 cells/mm3. Twelve (70.58%) of total patients were under low risk of essential thrombocythemia while 3 (17.64%) of them were at high risk. Conclusions: The prevalence of essential thrombocythemia was similar to other studies done in similar settings.

Clinical characteristics, prognostic factors, and outcomes of patients with essential thrombocythemia in Japan: the JSH-MPN-R18 study

We conducted a large-scale, nationwide retrospective study of Japanese patients who were diagnosed with essential thrombocythemia based on the diagnostic criteria in the World Health Organization classification. We investigated clinical characteristics, survival rates, and the incidence of thrombohemorrhagic events as well as risk factors for these events. A total of 1152 patients were analyzed in the present study. Median age at diagnosis was 65 years, the median platelet count was 832 × 10⁹/L, and the positive mutation rates of JAK2V617F, CALR, and MPL were 62.8, 25.1, and 4.1%, respectively. Compared with European and American patients, Japanese patients were more likely to have cardiovascular risk factors and less likely to have systemic symptoms including palpable splenomegaly. Thrombocytosis was identified as a risk factor for hemorrhagic events and prognosis, but not for thrombotic events. The prognostic factors and risk classifications reported in Europe and the United States were generally applicable to Japanese patients. Regarding transformations, secondary myelofibrosis progressed in a time-dependent manner, but progression to acute leukemia was low in "true" ET patients. Skin cancers were less common and gastrointestinal cancers more common as secondary malignancies in Japanese patients, suggesting ethnic differences.

The Epidemiology of Myeloproliferative Neoplasms in New Zealand between 2010 and 2017: Insights from the New Zealand Cancer Registry

BACKGROUND

There is a paucity of data on ethnic disparities in patients with the classical Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs): polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF).

METHODS

This study analysed the demographic data for PV, ET and PMF collected by the New Zealand Cancer Registry (NZCR) between 2010 and 2017.

RESULTS

We found that the NZCR capture rates were lower than average international incidence rates for PV and ET, but higher for PMF (0.76, 0.99 and 0.82 per 100,000, respectively). PV patients were older and had worse outcomes than expected, which suggests these patients were reported to the registry at an advanced stage of their disease. Polynesian patients with all MPN subtypes, PV, ET and PMF, were younger than their European counterparts both at the time of diagnosis and death (p < 0.001). Male gender was an independent risk factor for mortality from PV and PMF (hazard ratios (HR) of 1.43 and 1.81, respectively; p < 0.05), and Māori ethnicity was an independent risk factor for mortality from PMF (HR: 2.94; p = 0.006).

CONCLUSIONS

New Zealand Polynesian patients may have increased genetic predisposition to MPN, thus we advocate for modern genetic testing in this ethnic group to identify the cause. Further work is also required to identify modifiable risk factors for mortality in MPN, in particular those associated with male gender and Māori ethnicity; the results may benefit all patients with MPN.

Among classic myeloproliferative neoplasms, essential thrombocythemia is associated with the greatest risk of venous thromboembolism during COVID-19

In a multicenter European retrospective study including 162 patients with COVID-19 occurring in essential thrombocythemia (ET, n = 48), polycythemia vera (PV, n = 42), myelofibrosis (MF, n = 56), and prefibrotic myelofibrosis (pre-PMF, n = 16), 15 major thromboses (3 arterial and 12 venous) were registered in 14 patients, of whom all, but one, were receiving LMW-heparin prophylaxis. After adjustment for the competing risk of death, the cumulative incidence of arterial and venous thromboembolic events (VTE) reached 8.5% after 60 days follow-up. Of note, 8 of 12 VTE were seen in ET. Interestingly, at COVID-19 diagnosis, MPN patients had significantly lower platelet count (p < 0.0001) than in the pre-COVID last follow-up.This decline was remarkably higher in ET (-23.3%, p < 0.0001) than in PV (-16.4%, p = 0.1730) and was associated with higher mortality rate (p = 0.0010) for pneumonia. The effects of possible predictors of thrombosis, selected from those clinically relevant and statistically significant in univariate analysis, were examined in a multivariate model. Independent risk factors were transfer to ICU (SHR = 3.73, p = 0.029), neutrophil/lymphocyte ratio (SHR = 1.1, p = 0.001) and ET phenotype (SHR = 4.37, p = 0.006). The enhanced susceptibility to ET-associated VTE and the associated higher mortality for pneumonia may recognize a common biological plausibility and deserve to be delved to tailor new antithrombotic regimens including antiplatelet drugs.

The Current Status of Screening for Essential Thrombocythemia and Polycythemia Vera in Clinical Practice-Report from a Single Institution

OBJECTIVE

We investigate the current status of screening for essential thrombocythemia(ET)and polycythemia vera(PV), at our hospital.

METHODS

According to the World Health Organization(WHO)diagnostic criteria.

PATIENTS

All patients who visited Juntendo University Urayasu Hospital between May 1984(when the hospital opened)and January 2019.

RESULT

More than 90% of patients with elevated platelet counts(PLT)(n=25,062)and more than 90% of patients with elevated hemoglobin( Hb)or hematocrit(Ht)levels(n=16,422)did not visit the department of hematology, suggesting that there could be a high percentage of patients with potentially latent ET and PV visiting the hospital. In addition, a large number of patients fulfilling the laboratory criteria for ET/PV visited various departments of the hospital other than the department of hematology.

CONCLUSION

Because ET/PV manifests with diverse symptoms, including non-specific symptoms and symptoms pertaining to other organ systems. Based on the findings, we consider that it is essential to disseminate information about the WHO diagnostic criteria/clinical symptoms and possibility of latent ET/PV to all departments of the hospital, and to establish cooperation between the department of hematology and other departments.

Anagrelide influences thrombotic risk, and prolongs progression-free and overall survival in essential thrombocythaemia vs hydroxyurea plus aspirin

OBJECTIVE

We report an extension study of patients with essential thrombocythaemia (ET) in the Hungarian Myeloproliferative Neoplasm (HUMYPRON) Registry, which demonstrated that over 6 years anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous thrombotic events (TEs) vs hydroxyurea+aspirin.

METHODS

Data on patients with ET were collected through completion of a questionnaire developed according to 2008 WHO diagnostic criteria and with regard to Landolfi, Tefferi and IPSET criteria for thrombotic risk. Data were entered into the registry from 14 haematological centres. TEs, secondary malignancies, disease progression and survival were compared between patients with ET treated with anagrelide (n = 116) and with hydroxyurea+aspirin (n = 121).

RESULTS

Patients were followed for (median) 10 years. A between-group difference in the number of patients with TEs was observed (25.9% anagrelide vs 38.0% hydroxyurea+aspirin; P = .052). Minor arterial events were more frequently reported in the hydroxyurea+aspirin group (P < .001); there were marginally more reports of major arterial events in the anagrelide group (P = .049). TE prior to diagnosis was found to significantly influence TE incidence (P > .001). Progression-free survival (P = .004) and survival (P = .001) were significantly increased for the anagrelide group vs hydroxyurea+aspirin.

CONCLUSIONS

Anagrelide reduced TEs, and increased progression-free and overall survival vs hydroxyurea+aspirin over (median) 10 years.

Late polycythemic transformation in JAK2-mutated essential thrombocythemia patients-characteristics along with a validation of 2016 WHO criteria

INTRODUCTION AND OBJECTIVES

The most common mutation within the spectrum of myeloproliferative neoplasms (MPNs) is a mutation in Janus kinase 2 gene (JAK2V617F). It has been observed that, during a course of disease, transformation from JAK2-mutated essential thrombocythemia (ET) to overt polycythemia vera (PV) can occur. Primary objective of this study was to show the incidence of mentioned phenomenon.

METHODS

In this study, we analyzed data of 136 patients diagnosed with JAK2-positive ET observed for a median time of 9 years. We examined blood count of each patient at the time of diagnosis and confronted it with 2008 and 2016 WHO criteria for PV and mPV. Additionally, we analyzed JAK2V617F allele burden in two separate time points among selected cases.

RESULTS

Confrontation with new criteria resulted in change of diagnosis to PV and mPV in 10% and 9% cases, respectively. Within remaining patients, 14 showed increasing hemoglobin concentration over several months during late course of disease, resulting in change of diagnosis to overt PV. We did not find suggested increase in JAK2 allele burden among transforming patients.

CONCLUSIONS

Phenotype transformation to polycythemia was proven to be possible within the group of JAK2-mutated ET; however, cause of this effect remains uncertain.

Analysis of clinical characteristics of bone marrow proliferative tumor progression to acute myeloid leukemia

OBJECTIVE

This study aims to analyze Chinese patients who developed acute leukemia after being diagnosed and treated for Philadelphia chromosome (Ph)-negative chronic myeloproliferative neoplasms (MPNs), and compare the findings of this series with similar studies from literature.

METHODS

Nine patients who progressed to leukemia after being diagnosed with MPN were included into the present study. Clinical data including age, treatment modalities and duration of use in the myeloproliferative phase, latency to leukemic transformation (LT), characteristics of leukemia, chemotherapy administration, and survival after LT were examined. Furthermore, factors associated with leukemia transformation were analyzed.

RESULTS

Over a 13-year period, nine patients had LT in 192 Ph-negative MPNs. Among these patients, two patients had polycythemia vera (PV), three patients had essential thrombocythemia (ET), and four patients had myelofibrosis (MF). The median age at MPN diagnosis was 51 years old (range: 42-69 years old), and the median age upon reaching LT was 57 years old (range: 46-72 years old). Furthermore, the median latency to LT was 72.8 months (range: 7-144 months). Five patients had cytogenetic abnormalities (62.5%), with abnormalities in chromosomes -5, +8 and -7 being common. Eight patients underwent the JAK2 V617F gene test when diagnosed with MPN. The prognosis of patients with LT was poor, and the average survival time was 6.7 months. This was not correlated with the treatment.

CONCLUSION

LT in Ph-negative MPNs is rare, and has poor prognosis, which has been consistently reported in a number of studies, However, this needs to be further confirmed through larger studies.

Incidence, Survival and Prevalence Statistics of Classical Myeloproliferative Neoplasm in Korea

The nationwide statistical analysis of each disease of classical myeloproliferative neoplasm (MPN) in Korea has not been reported yet. To this end, we have analyzed incidence rates, survival rates and treatment pattern of polycythemia vera (PV), primary myelofibrosis (MF) and essential thrombocythemia (ET) using Korea National Cancer Incidence Database (KNCIDB) and Health Insurance Review and Assessment Service (HIRA) database. Between 2003 and 2011, a total of 4,342 new cases of MPN were reported to the KNCIDB. ET was the most common, followed by MF and PV. The crude incidence rates for PV, MF, and ET have increased during the period, reaching 0.40, 0.15, and 0.84 per 100,000, respectively. Five-year relative survival rate of all MPN patients was 89.3%, with lowest relative survival rate with MF (53.1%). The prevalence of each disease estimated from HIRA data also increased during the study period. Notably, ET was found to be most prevalent. The prescription rate of hydroxyurea and phlebotomy to PV, MF and ET patients remained constant over the period, and the prescription rate of hydroxyurea was higher in patients with age over 60 years. This is the first Korean nationwide statistics of MPN, using central registry data. This set of data can be utilized to compare the Korean MPN status to international data and guidelines.

Spleen enlargement is a risk factor for thrombosis in essential thrombocythemia: Evaluation on 1,297 patients

Spleen enlargement, present in 10-20% of Essential Thrombocythemia (ET) patients at diagnosis, is a feature clinically easy to assess, confirmable by echography with a very low chance of misinterpretation. Nonetheless, the clinical and prognostic role of splenomegaly has been seldom evaluated. From 1979 to 2013, 1297 ET patients retrospectively collected in the database of the Lazio Cooperative Group and Bologna University Hospital were evaluable for spleen enlargement at diagnosis and included in the analysis. On the whole, spleen was enlarged in 172/1297 (13.0%) patients; in most cases (94.8%) splenomegaly was mild (≤5 cm). Patients with splenomegaly were younger, predominantly male, presented higher platelet count and JAK2V617F allele burden and had a lower incidence of concomitant cardiovascular risk factors. At least one thrombotic event during follow-up occurred in 97/1,125 (8.6%) patients without spleen enlargement compared to 27/172 (15.7%) patients with spleen enlargement (P = 0.003). Despite comparable use of cytoreductive/antiplatelet therapies in the two groups, the cumulative risk of thrombosis at 5 years was significantly higher in patients with baseline splenomegaly (9.8% versus 4.4% in patients without splenomegaly, P = 0.012). In multivariate analysis exploring risk factors for thrombosis, splenomegaly retained its negative prognostic role, together with previous thrombosis, leucocyte count and male gender. Baseline splenomegaly seems to be an independent additional risk factor for thrombosis in nonstrictly WHO-defined ET patients. This data could be useful in the real-life clinical management of these patients.

Frequencies, Laboratory Features, and Granulocyte Activation in Chinese Patients with CALR-Mutated Myeloproliferative Neoplasms

Somatic mutations in the CALR gene have been recently identified as acquired alterations in myeloproliferative neoplasms (MPNs). In this study, we evaluated mutation frequencies, laboratory features, and granulocyte activation in Chinese patients with MPNs. A combination of qualitative allele-specific polymerase chain reaction and Sanger sequencing was used to detect three driver mutations (i.e., CALR, JAK2V617F, and MPL). CALR mutations were identified in 8.4% of cases with essential thrombocythemia (ET) and 5.3% of cases with primary myelofibrosis (PMF). Moreover, 25% of polycythemia vera, 29.5% of ET, and 48.1% of PMF were negative for all three mutations (JAK2V617F, MPL, and CALR). Compared with those patients with JAK2V617F mutation, CALR-mutated ET patients displayed unique hematological phenotypes, including higher platelet counts, and lower leukocyte counts and hemoglobin levels. Significant differences were not found between Chinese PMF patients with mutants CALR and JAK2V617F in terms of laboratory features. Interestingly, patients with CALR mutations showed markedly decreased levels of leukocyte alkaline phosphatase (LAP) expression, whereas those with JAK2V617F mutation presented with elevated levels. Overall, a lower mutant rate of CALR gene and a higher triple-negative rate were identified in the cohort of Chinese patients with MPNs. This result indicates that an undiscovered mutant gene may have a significant role in these patients. Moreover, these pathological features further imply that the disease biology varies considerably between mutants CALR and JAK2V617F.

Contribution of cardiovascular risk factors in the thrombotic complications of essential thrombocythaemia: a Hungarian single-institute retrospective analysis

OBJECTIVE

Essential thrombocythaemia (ET) is a myeloproliferative neoplasm in which there is an increased risk of thrombotic complications. The conventional thrombosis risk assessment of these patients is based on an age over 60 and a history of thrombosis. The aim of this report is to analyse the contribution of cardiovascular risk (CV) factors as possible additional thrombotic risk factors in the thrombotic complications seen in ET.

PATIENTS AND METHODS

One hundred and one ET patients (72 females and 29 males with a median age of 61 years) were enrolled between 1999 and 2011. Mann-Whitney and multivariate binary logistic regression tests were performed. The Kaplan-Meier method followed by the log-rank test was used to evaluate the probability of thrombosis-free survival.

RESULTS

The presence of one or two or more CV risk factors significantly increased the risk of thrombosis. Separately, the contribution of high blood pressure and hyperlipidaemia proved to be influential, whereas tobacco use, diabetes mellitus and obesity were not significant. Significant differences were revealed in the probability of thrombosis-free survival between patients without CV risk factors and those with at least one CV risk factor, and between those with at most one CV risk factor and those with two or more CV risk factors.

CONCLUSIONS

On the basis of the results on the current cohort, it is suggested that CV risk factors may influence the thrombotic complications in ET.

The role of genotypes that modify the toxicity of chemical mutagens in the risk for myeloproliferative neoplasms

BACKGROUND

The etiology of myeloproliferative neoplasms (MPN) (polycythemia vera; essential thrombocythemia; primary myelofibrosis) is unknown, however they are associated with a somatic mutation--JAK2 V617F--suggesting a potential role for environmental mutagens.

METHODS

We conducted a population-based case-control study in three rural Pennsylvania counties of persons born 1921-1968 and residing in the area between 2000-2008. Twenty seven MPN cases and 292 controls were recruited through random digit dialing. Subjects were genotyped and odds ratios estimated for a select set of polymorphisms in environmentally sensitive genes that might implicate specific environmental mutagens if found to be associated with a disease.

RESULTS

The presence of NAT2 slow acetylator genotype, and CYP1A2, GSTA1, and GSTM3 variants were associated with an average 3-5 fold increased risk.

CONCLUSIONS

Exposures, such as to aromatic compounds, whose toxicity is modified by genotypes associated with outcome in our analysis may play a role in the environmental etiology of MPNs.

Thrombosis and risk factors in female patients with a rare acquired thrombophilia: chronic myeloproliferative disorder - polycythaemia vera and essential thrombocythaemia

OBJECTIVE

In polycythaemia vera (PV) and essential thrombocythaemia (ET), the life expectancy of the patients is greatly affected by thrombotic events. An investigation was performed of the potential association of PV/ET, and thrombotic complications with cardiovascular (CV) risk factors, a leukocyte count at the haematological diagnosis > 11.1 G/L, and the JAK2V617F mutation.

PATIENTS AND METHODS

In the period 1998-2011, 128 women with a median age of 62 years were enrolled.

RESULTS

The risk of thrombotic events before the diagnosis was 32.8% (42/128), while in the follow-up period it was 10.2% (13/128). The difference in the probability of thrombosis-free survival between those with at most one CV risk factor and those with two or more CV risk factors was significant (p = 0.005). The presence of two or more CV risk factors (univariate: p = 0.011; multivariate: relative risk: 4.728, 95% CI 1.312-17.040; p = 0.018) significantly increased the risk of thrombosis. Univariate analyses revealed that high blood pressure (p = 0.001), hyperlipidaemia (p = 0.005) and cigarette smoking (p = 0.051) were associated with a significantly higher risk of thrombosis. Analyses of the influence of the leukocyte count (univariate: p = 0.424; multivariate: relative risk: 1.407, 95% CI 0.359-5.507; p = 0.624) and the JAK2V617F mutation (univariate: p = 0.367; multivariate: relative risk: 1.428, 95% CI 0.316-6.460; p = 0.643) on subsequent thrombotic complications resulted in a non-signicant tendency.

CONCLUSIONS

Female patients who display CV risk factors (high blood pressure, hyperlipidaemia and/or cigarette smoking) and PV or ET may well be at a higher risk of thrombotic events and require special consideration as concerns as the prevention and management of thrombotic events.

Thrombotic complications of myeloproliferative neoplasms: risk assessment and risk-guided management

Philadelphia-negative myeloproliferative neoplasms are considered to be acquired thrombophilic states. Thromboses, both arterial and venous (not rarely in unusual sites), are often the initial events leading to the diagnosis. After diagnosis, the yearly incidence of thrombotic events is highly variable, and ranges from approximately 1% to 10%. The identification of patients at risk who may benefit from antithrombotic therapy remains a challenge, and it is currently based on age and history of thrombotic events. However, the predictive value of these clinical characteristics is rather limited. Few prospective studies and even fewer interventional randomized studies are available, and there are no studies designed to formally validate the use of risk stratification. The implementation of laboratory parameters such as leukocytosis and/or the JAK2 V617F mutation into a scoring system may be of interest. The mechanisms at work leading to thrombosis remain largely speculative, but are likely to be complex and multifactorial, with a prominent role of cell-cell interactions, mostly owing to qualitative changes. The long-term treatment options to prevent thrombosis are, schematically, aspirin alone as primary prevention for the low-risk patients, and cytoreduction combined with aspirin for the other patients. In very low-risk young essential thrombocythemia patients, abstention can even be considered. The optimal duration of anticoagulation after a thrombotic event is not established. All antithrombotic therapies should be balanced with the hemorrhagic risk, which can also be increased in these patients.

JAK2-v617F mutation is associated with clinical and laboratory features of myeloproliferative neoplasms

The aim of this study is to investigate the differences of clinical and laboratory parameters between patients with JAK2-V617F positive myeloproliferative neoplasms (MPNs) and JAK2 wild type MPNs. DNA was isolated from peripheral blood granulocytes of 106 patients treated at Rijeka University Hospital Center: 41 with polycythemia vera (PV), 43 with essential thrombocythemia (ET), 9 with primary myelofibrosis (PMF) and 13 with myeloproliferative neoplasm--unclassifiable (MPN-u). The JAK2-V617F mutation was detected using allele specific PCR. Laboratory and clinical parameters were obtained from patient's medical records. The JAK2-V617F mutation was detected in 69% (73/106) patients with MPNs. The results revealed significantly different prevalence of JAK2-V617F mutation, between MPNs entities: 88% in PV 58% in ET, 56% in PMF and 54% in MPNs-unclassified disorders. The JAK2-V617F mutation significantly correlated with higher leukocyte count and alkaline phosphatase co re in ET group and with higher platelets count, leukocyte alkaline phosphatase score and serum lactate dehydrogenase in PV group. Vascular events were associated with elevated platelets count in whole MPNs group, with higher platelets and leukocyte count in ET and with splenomegaly in PVpatients. Clinical and laboratory data revealed significant contribution ofJAK2-V617F mutation to the development of clinical phenotype in patients with distinct subgroups of MPNs.

Polycythemia vera and essential thrombocythemia: 2012 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms primarily characterized by erythrocytosis and thrombocytosis, respectively. Other disease features include leukocytosis, splenomegaly, thrombohemorrhagic complications, vasomotor disturbances, pruritus, and a small risk of disease progression into acute myeloid leukemia or myelofibrosis.

DIAGNOSIS

Almost all patients with PV harbor a JAK2 mutation. When PV is suspected, the presence of a JAK2 mutation confirms the diagnosis and its absence, combined with normal or increased serum erythropoietin level, excludes the diagnosis. Differential diagnosis of ET had to include chronic myelogenous leukemia and prefibrotic myelofibrosis. A JAK2 mutation is found in approximately 60% of patients with ET.

RISK STRATIFICATION

Current risk stratification in PV and ET is designed to estimate the likelihood of thrombotic complications: 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. Presence of extreme thrombocytosis (platelet count >1,000 × 10(9)/L) might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding. Risk factors for shortened survival in both PV and ET include advanced age, leukocytosis, and history of thrombosis.

RISK-ADAPTED THERAPY

Survival is near-normal in ET and reasonably long in PV. The 10-year risk of leukemic/fibrotic transformation is <1%/1% in ET and <3%/10% in PV. In contrast, the risk of thrombosis exceeds 20%. The main goal of therapy is therefore to prevent thrombohemorrhagic complications and this is effectively and safely accomplished by the use of low-dose aspirin (PV and ET), phlebotomy (PV) and hydroxyurea (high risk PV and ET). Treatment with busulfan or interferon-α is usually effective in hydroxyurea failures. Screening for clinically significant AvWS is recommended before administrating aspirin in the presence of extreme thrombocytosis.

Leukocytosis is a risk factor for recurrent arterial thrombosis in young patients with polycythemia vera and essential thrombocythemia

There is evidence that leukocytosis is associated with an increased risk of first thrombosis in patients with polycythemia vera (PV) and essential thrombocythemia (ET). Whether it is a risk factor for recurrent thrombosis too is currently unknown. In the frame of a multicenter retrospective cohort study, we recruited 253 patients with PV (n = 133) or ET (n = 120), who were selected on the basis of a first arterial (70%) or venous major thrombosis (27.6%) or both (2.4%), and who were not receiving cytoreduction at the time of thrombosis. The probability of recurrent thrombosis associated with the leukocyte count recorded at the time of the first thrombosis was estimated by a receiver operating characteristic analysis and a multivariable Cox proportional hazards regression model. Thrombosis recurred in 78 patients (30.7%); multivariable analysis showed an independent risk of arterial recurrence (hazard ratio [HR] 2.16, 95% CI 1.12-4.18) in patients with a leukocyte count that was >12.4 x 10(9)/L at the time of the first thrombotic episode. The prognostic role for leukocytosis was age-related, as it was only significant in patients that were aged <60 years (HR for arterial recurrence 3.35, 95% CI 1.22-9.19).

Blast phase of essential thrombocythemia: A single center study

Blast phase (BP) may occur as a late event in essential thrombocythemia (ET). This study includes 19 patients with post-ET BP diagnosed and followed in a single institution. At BP, 63% of patients had leukocytosis (white blood cell count >10 x 10(9)/L), 74% had anemia (hemoglobin value <10 g/dL), 74% had thrombocytopenia (platelet count <100 x 10(9)/L), and 84% were over 65 years of age. Cytogenetic analysis was available in 10 patients: six had karyotype aberrations. According to cytogenetic-based risk stratification of de novo acute leukemia (AL), all patients had an unfavorable profile. JAK2 (V617F) mutational status was evaluated in five patients. In two of them, the JAK2 mutation was undetectable in blast cells (one with JAK2-positive ET), whereas in three both granulocytes and blast cells displayed the mutation. Treatment of BP was patient-based according to the performance status and co-morbidities and consisted of palliation in 14 patients, and of induction of remission in five. Median survival was 2.3 months (range 0.2-22.3), irrespective of the treatment received. In conclusion, this study indicates that AL evolved from ET has unfavorable clinical and biological features. JAK2 (V617F)-positive ET may evolve in few instances into JAK2-negative leukemia. The outcome of patients is poor whatever the treatment used.

Essential thrombocythemia: past and present

Essential thrombocythemia (ET) is a clonal myeloproliferative disorder characterized by sustained increase in platelet number and tendency for thromboembolism. A somatic point mutation that causes a constitutive activation of the JAK2 gene is found in one in two ET patients. ET is more common in women, its incidence being 0.6-2.5/100,000 patient/year and the median age at diagnosis is 65-70 years. ET can affect all age groups, including children (0.09 cases/year), and is often diagnosed in the third-fourth decade of life. Rare cases of familial ET have been reported. Miscarriages are 3-4 times more common among women with ET than in the general population, especially in patients carrying JAK2V617F. Microvascular disturbances are typical of ET, but a major thrombosis (2/3 arterial and 1/3 venous; 1, 2-3% patient/year) is the main cause of morbidity and mortality. Age over 60 years and/or previous thrombosis are validated risk factor for thrombosis. Hemorrhages occur in 0.33% patient/year, mainly in those with a platelet count over 1,500 x 10(9)/L. Progression to myelofibrosis and leukemia is more common in patients carrying the JAK2V617F mutation, and is estimated to occur in 0.16% and 0.12% patient/year, respectively. The ET-related mortality ratio with respect to the general population is 1:1, while for polycythemia vera it is 1.6:1. Low-dose aspirin is useful for microvascular disturbances, and in the primary and secondary prevention of major thrombosis in high-risk patients, but it is not recommended in patients with a platelet count over 1,500 x 10(9)/L. Hydroxyurea is used as first-line treatment in high-risk patients. Other drugs available are alpha-interferon, anagrelide, pipobroman and busulphan.

Prevalence of polycythemia vera and essential thrombocythemia

Polycythemia vera (PV) and essential thrombocythemia (ET) are common types of myeloproliferative disorders (MPD), the prevalence of which has not been well documented in the United States. Recent breakthroughs in the molecular etiology of these disorders and the accelerated development of targeted pharmacotherapeutics to treat them underscore the need to define the affected population. In this study, we obtained health claims data from major commercial insurance payers in Connecticut and the Center for Medicare and Medicaid Services to estimate the prevalence of PV and ET. Specifically, logistic regression was utilized to develop algorithms to predict the probability that an individual with claims suggestive of MPD truly has PV or ET, and the algorithms were then applied to health claims to estimate the number of PV and ET patients in Connecticut. As of 2003, the age-standardized prevalence was 22 per 100,000 and 24 per 100,000 for PV and ET, respectively, in Connecticut. Applying the age-specific prevalence of PV and ET to the entire US population resulted in an estimated total of 65,243 patients with PV and 71,078 patients with ET in the United States in 2003. This study is the first to assess the prevalence of PV and ET in a large US population. Given the large number of individuals afflicted with these diseases and the fact that demographic changes alone will further increase the burden of

Essential thrombocythemia in young individuals: frequency and risk factors for vascular events and evolution to myelofibrosis in 126 patients

The frequency of vascular events and evolution to myelofibrosis (MF) in young individuals with essential thrombocythemia (ET) is not well known. The incidence and predisposing factors to such complications was studied in 126 subjects diagnosed with ET at a median age of 31 years (range: 5-40). Overall survival and probability of survival free of thrombosis, bleeding and MF were analyzed by the Kaplan-Meier method and the presence of the Janus Kinase 2 (JAK2) V617F mutation correlated with the appearance of such complications. The JAK2 mutation (present in 43% of patients) was associated with higher hemoglobin (Hb) (P<0.001) and lower platelets at diagnosis. With a median follow-up of 10 years (range: 4-25), 31 thrombotic events were registered (incidence rate: 2.2 thromboses/100 patients/year). When compared with the general population, young ET patients showed a significant increase in stroke (odds ratio 50, 95% CI: 21.5-115) and venous thromboses (odds ratio 5.3, 95% CI: 3.9-10.6). Thrombosis-free survival was 84% at 10 years, with tobacco use being associated with higher risk of thrombosis. Actuarial freedom from evolution to MF was 97% at 10 years. In conclusion, young ET patients have thrombotic events, especially stroke and venous thrombosis, more frequently than generally considered, whereas they rarely transform to MF.

Increased risk of pregnancy complications in patients with essential thrombocythemia carrying the JAK2 (617V>F) mutation

Essential thrombocythemia (ET) may occur in women of childbearing age. To investigate the risk of pregnancy complications, we studied 103 pregnancies that occurred in 62 women with ET. The 2-tailed Fisher exact test showed that pregnancy outcome was independent from that of a previous pregnancy. The rate of live birth was 64%, and 51% of pregnancies were uneventful. Maternal complications occurred in 9%, while fetal complications occurred in 40% of pregnancies. The Mantel-Haenszel method showed that fetal loss in women with ET was 3.4-fold higher (95% confidence interval [CI]: 3-3.9; P < .001) than in the general population. Half of the women studied carried the JAK2 (617V>F) mutation, and a multivariate logistic regression model identified this mutation as an independent predictor of pregnancy complications (P = .01). Neither the platelet count nor the leukocyte count was a risk factor. JAK2 (617V>F)-positive patients had an odds ratio of 2.02 (95% CI: 1.1 - 3.8) of developing complications in comparison with JAK2 (617V>F)-negative patients. Aspirin did not prevent complication in JAK2 (617V>F)-positive patients and appeared to worsen outcome in JAK2 (617V>F)-negative patients. A relationship was found between JAK2 (617V>F) and fetal loss (P = .05). This study indicates that patients carrying the JAK2 (617V>F) mutation have higher risk of developing pregnancy complications.

Incidence of the JAK2 V617F mutation among patients with splanchnic or cerebral venous thrombosis and without overt chronic myeloproliferative disorders

BACKGROUND

Thrombosis of splanchnic or cerebral veins is a typical manifestation of polycythemia vera (PV) or essential thrombocythemia (ET). The recently identified Janus kinase 2 (JAK2) V617F somatic mutation is closely related to chronic myeloproliferative disorders (CMD).

OBJECTIVE

To assess the incidence of the JAK2 V617F mutation among patients with splanchnic or cerebral venous thrombosis with or without overt CMD.

PATIENTS AND METHODS

We searched for the mutation in 139 adult patients (> 18 years old) with thrombosis of hepatic veins (HVT, n = 15), or extrahepatic portal vein (PVT) and/or mesenteric vein (MVT) (n = 79), or cerebral veins (CVT, n = 45). Only 19 patients fulfilled criteria for diagnosis of PV (n = 8) or ET (n = 11) at the time of thrombosis: four had HVT, 11 PVT and/or MVT, and four CVT.

RESULTS

The JAK2 V617F mutation was found in 94.7% [95% CI 75.3-99.0] of the patients with overt CMD at the time of thrombosis, in 21.5% (95% CI 13.8-31.7) of the patients with abdominal venous thrombosis and without overt CMD, and in 4.8% (95% CI 1.3-16.1) of the patients with CVT and without overt CMD. Among the patients without overt CMD or thrombophilia and with unprovoked thrombosis, 29.4% (95% CI 16.8-46.1) with splanchnic venous thrombosis and 42.8% (95% CI 24.4-63.4) with PVT had the JAK2 V617F mutation.

CONCLUSIONS

A substantial proportion of patients with splanchnic venous thrombosis and a small, but significant, number of patients with CVT can be recognized as carriers of the JAK2 V617F mutation in the absence of overt signs of CMD. The clinical significance of such findings deserves further investigation.

Essential thrombocythemia

Essential thrombocythemia (ET) is an acquired myeloproliferative disorder (MPD) characterized by a sustained elevation of platelet number with a tendency for thrombosis and hemorrhage. The prevalence in the general population is approximately 30/100,000. The median age at diagnosis is 65 to 70 years, but the disease may occur at any age. The female to male ratio is about 2:1. The clinical picture is dominated by a predisposition to vascular occlusive events (involving the cerebrovascular, coronary and peripheral circulation) and hemorrhages. Some patients with ET are asymptomatic, others may experience vasomotor (headaches, visual disturbances, lightheadedness, atypical chest pain, distal paresthesias, erythromelalgia), thrombotic, or hemorrhagic disturbances. Arterial and venous thromboses, as well as platelet-mediated transient occlusions of the microcirculation and bleeding, represent the main risks for ET patients. Thromboses of large arteries represent a major cause of mortality associated with ET or can induce severe neurological, cardiac or peripheral artery manifestations. Acute leukemia or myelodysplasia represent only rare and frequently later-onset events. The molecular pathogenesis of ET, which leads to the overproduction of mature blood cells, is similar to that found in other clonal MPDs such as chronic myeloid leukemia, polycythemia vera and myelofibrosis with myeloid metaplasia of the spleen. Polycythemia vera, myelofibrosis with myeloid metaplasia of the spleen and ET are generally associated under the common denomination of Philadelphia (Ph)-negative MPDs. Despite the recent identification of the JAK2 V617F mutation in a subset of patients with Ph-negative MPDs, the detailed pathogenetic mechanism is still a matter of discussion. Therapeutic interventions in ET are limited to decisions concerning the introduction of anti-aggregation therapy and/or starting platelet cytoreduction. The therapeutic value of hydroxycarbamide and aspirin in high risk patients has been supported by controlled studies. Avoiding thromboreduction or opting for anagrelide to postpone the long-term side effects of hydrocarbamide in young or low risk patients represent alternative options. Life expectancy is almost normal and similar to that of a healthy population matched by age and sex.

Essential thrombocythemia/polycythemia vera and pregnancy: the need for an observational study in Europe

The management of pregnant patients with essential thrombocythemia (ET) and polycythemia vera (PV) may be problematic. In the literature there are approximately 300 cases of pregnancies reported in ET and less than 50 pregnancies reported in PV. To reduce the effect of reporting bias, we selected articles with either > 10 pregnancies or at least six patients, and here report on the outcome of 195 pregnancies in ET and 36 pregnancies in PV patients. The live birth rate was approximately 60% in ET and 58% in PV. Spontaneous abortion during the first trimester was the most frequent fetal complication, occurring in 31% of ET pregnancies and in 22% of PV pregnancies, respectively. Major maternal complications were more frequent in PV compared with ET (44.4 versus 7.7%). Treatment with low-dose aspirin during pregnancy in ET seemed to reduce complications and also seemed beneficial during pregnancy in PV. In high-risk pregnancies, the additional use of low molecular weight heparin and/or interferon alpha should be considered. This article also describes a registry for an observational study concerning pregnancy in chronic Philadelphia chromosome-negative myeloproliferative disorders within the European LeukemiaNet. A potential management algorithm for pregnancies in ET or PV is also provided.

Epidemiology of the Myeloproliferative Disorders Polycythemia Vera and Essential Thrombocythemia

The annual incidence of polycythemia vera (PV) and essential thrombocythemia (ET) is approximately 2 and 1.5 per 100,000 inhabitants, respectively, if based on large population surveys and adjusted to a standard population. Survival for ET patients does not differ from that of the general population. However, it appears that PV patients have a significantly higher mortality, at least for patients diagnosed before 1990.

Essential thrombocythemia

Significant progress in our understanding of the molecular pathogenesis of essential thrombocythemia (ET) and the other Philadelphia (Ph) chromosome-negative myeloproliferative disorders (MPDs) has recently been achieved. Unfortunately, the diagnosis of ET still relies on a set of exclusion criteria developed years ago, as recent advances have yet to be evaluated for this purpose. The clinical course of ET is characterized by an increased incidence of thrombotic and hemorrhagic complications and an inherent tendency to progress into myelofibrosis or acute myeloid leukemia (AML). There is concern about undesirable effects of cytoreductive therapy given to prevent vascular events, particularly the risk of accelerating the rate of hematologic transformation. Thus, management involves modification of reversible vascular risk factors and further stratification according to the thrombotic risk. Myelosuppressive agents are not recommended in low-risk patients, whereas controlled studies support the therapeutic value of hydroxyurea (HU) plus aspirin in high-risk cases. Anagrelide or interferon-alpha (IFN-alpha) could be considered as second-line therapy in patients refractory or intolerant of HU. IFN-alpha is preferred in pregnant women.

Mutation of the prothrombin gene and thrombotic events in patients with polycythemia vera or essential thrombocythemia: a cohort study

The association between a prothrombin mutation and the risk of thrombosis was analyzed in 214 patients with polycythemia vera or essential thrombocythemia. The rate for venous thrombotic events was 14.7/100 patient-years in patients with the prothrombin mutation compared to 0.8 in patients without the mutation (rate ratio 17.5).

Pregnancy in essential thrombocythaemia: experience with 40 pregnancies

In this study, the course of 40 pregnancies in 16 women with essential thrombocythaemia (ET) was analysed retrospectively. Of the pregnancies, 45% were complicated, 55% uncomplicated, and 62% resulted in live birth. The most common complication was spontaneous abortion during the first trimester seen in 33% of all pregnancies and comprising 72% of all complications. Two intrauterine foetal deaths occurred at weeks 22 and 28. Three pregnancies were complicated by eclampsia or pre-eclampsia. Nine of 16 women with 29 pregnancies had at least one complicated pregnancy. In seven of 16 women, all 11 pregnancies were uneventful. The non-pregnancy-related symptoms of ET or the platelet count before conception or during pregnancy did not correlate with the risk of pregnancy complications. Treatment with low-dose acetylsalicylic acid (ASA) alone during pregnancy or platelet-lowering drugs before or during pregnancy reduced the risk of complications.

Pathogenesis and management of bleeding in essential thrombocythemia and polycythemia vera

Patients with essential thrombocythemia (ET) and polycythemia vera (PV) have a paradoxical predisposition to bleeding and thrombotic complications that are major causes of morbidity and mortality. Bleeding manifestations are often associated with extreme thrombocytosis that may lead to acquired von Willebrand syndrome (AVWS). Symptomatic AVWS, in this instance, is managed by platelet cytoreductive therapy and, in case of a life-threatening situation, platelet apheresis may be of additional value. Qualitative platelet defects are prevalent in PV and ET but have not been consistently linked to clinical bleeding. However, in vitro and in vivo hemostatic defects in these disorders are either precipitated or exacerbated by the use of aspirin or other nonsteroidal anti-inflammatory drugs. Additional patient management issues are raised during systemic anticoagulation and surgery. This review summarizes putative pathogenetic mechanisms of bleeding and their management in ET and PV.

Essential thrombocythemia

Essential thrombocythemia is a distinct clinical entity within the spectrum of myeloproliferative disorders. There is as yet no pathognomonic diagnostic test, and patients who currently fall into the category of essential thrombocythemia are likely to be heterogeneous. This article discusses diagnostic criteria, clinical features, prognosis, and management.

The rate of progression to polycythemia vera or essential thrombocythemia in patients with erythrocytosis or thrombocytosis

BACKGROUND

The clinical relevance of mild erythrocytosis (hematocrit > 0.48 in women or > 0.51 in men) or thrombocytosis (platelet count > 400 x 10(9) cells/L) in asymptomatic persons is uncertain.

OBJECTIVE

To estimate the frequency of polycythemia vera or essential thrombocythemia in persons with erythrocytosis or thrombocytosis in a general population.

DESIGN

Cohort study.

SETTING

Vicenza, Italy.

PARTICIPANTS

10 000 community dwellers age 18 to 65 years and enrolled in the Vicenza Thrombophilia and Atherosclerosis project.

MEASUREMENTS

Platelet count and hematocrit at baseline in all participants and at second follow-up if baseline results were abnormal. Measurement of erythrocyte sedimentation rate, peripheral arterial saturation, serum erythropoietin level, and leukocyte alkaline phosphatase level; chest radiography; abdominal ultrasonography; and occult fecal blood testing were done in persons with confirmed high hematocrit or platelet counts. Polycythemia vera and essential thrombocythemia were diagnosed according to the Polycythemia Study Group criteria.

RESULTS

At baseline examination, 1 person had polycythemia vera, 1 had essential thrombocythemia, 88 had erythrocytosis, and 99 had thrombocytosis. Second examination confirmed erythrocytosis in 40% (95% CI, 29% to 51%) and thrombocytosis in 8% (CI, 4% to 15%) of those with abnormal baseline results. Among persons with confirmed abnormalities, further evaluation revealed 11 with idiopathic erythrocytosis, 2 with polycythemia vera (3/10 000 [CI, 0.6 to 8.7/10 000]), and 3 with essential thrombocythemia (4/10 000 [CI, 1.09 to 10.2/10 000]). After 5 years of follow-up, 1 additional person with a high platelet count developed essential thrombocythemia, and no persons developed hemorrhagic or thrombotic complications.

CONCLUSIONS

The prevalences of polycythemia vera and essential thrombocythemia were higher than expected in this general population. However, the risks for developing polycythemia vera, essential thrombocythemia, or associated vascular complications in persons with erythrocytosis or thrombocytosis were low.

[Occupational and environmental risk factors for essential thrombocythemia: a case-control study]

BACKGROUND

Essential Thrombocythemia (ET) is a chronic myeloproliferative disorder characterized by a long median survival, even though serious complications such as acute hemorrhagic or thrombotic events are not infrequent. Very few information are available about risk factors for ET because of lack of epidemiological studies focused on this topic.

METHODS

We conducted a case-control study in order to analyze the possible association between ET and some occupational and environmental risk factors. A total of 93 patients enrolled in two hospitals in Turin (Italy) and 280 subjects randomly selected from the general population as controls, were included in the analysis.

RESULTS

We found an association between ET and selected occupations. OR estimates suggest a significant association between ET cooks/waiters (OR 4.96, CI 1.59-16.9) and clerks (OR 2.63, CI 1.53-4.51) and a non significant association between ET and hairdressers (OR 5.10, CI 0.82-31.4), nurses (OR 3.75, CI 0.80-19.4), farmers (OR 1.74, CI 0.84-3.56), electricians (OR 1.42, CI 0.48-3.78), and photographers (OR infinity). Data did not suggest any strong association between environmental risk factors and ET.

CONCLUSIONS

Selected occupations seem to be associated to ET. The association of ET with occupations as hairdressers, farmers and electricians could be attributable to known risk factors for other hematolymphopoietic malignancies such as hair dye, pesticides and magnetic fields. The association with other occupations is more difficult to explain, but all the results we presented are consistent with data from previous studies on onco-hematological diseases.

Treatment indications and choice of a platelet-lowering agent in essential thrombocythemia

The therapeutic strategy in patients with essential thrombocythemia (ET) is a difficult balance between the prevention of bleeding and thrombotic complications and the risks of drug side effects and toxicity. Major bleeding is rare and seems to be related to higher platelet counts. Therefore, a platelet count greater than 1500 x 10(9)/L is generally regarded as an indication for cytoreduction. Thrombotic complications include microvascular occlusive symptoms, which are usually reversible with low-dose aspirin, and large vessel thrombosis. The risk of major thrombosis is higher in patients with ET who are older than 60 years and who have had a previous occlusive event. In this high-risk group, the nonalkylating agent hydroxyurea significantly reduces the rate of vascular complications and has emerged as the treatment of choice. However, the long-term risk:benefit ratio of hydroxyurea remains disputed because its leukemogenic potential has not been ruled out. This holds also for other myelosuppressive agents such as busulfan and pipobroman. Other drugs of particular interest for young patients include recombinant interferon-alpha and anagrelide. Both of these drugs are effective in lowering platelet counts, but their efficacy in reducing clinical complications remains to be demonstrated. Furthermore, interferon and anagrelide have frequent and clinically important side effects. Thus, further clinical studies are required to establish their role in the management of patients with ET.