Pregnancy outcomes in myeloproliferative neoplasms: UK prospective cohort study

Topics of Interest in Women With Myeloproliferative Neoplasms

OVERVIEW

Sex and gender have emerged as central modifiers of disease biology, phenotype, and clinical outcomes in myeloproliferative neoplasms (MPNs). This review will uniquely highlight issues affecting women with MPN and articulate their relevant determinants.

EPIDEMIOLOGY AND DIAGNOSIS

A higher overall prevalence of MPN has been established in women. The incidence of essential thrombocythemia (ET) predominates, while, conversely, polycythemia vera (PV) and myelofibrosis (MF) are seen in lower frequencies as compared to men. Diagnostic criteria are dictated by sex-driven physiological variances in hemoglobin and hematocrit levels in PV, mandating separate diagnostic thresholds, respectively: > 16.0 g/dL and > 48% in women vs. > 16.5 and > 49% in men.

GENETIC FRAMEWORK AND PHENOTYPE

Women with MPN harbor fewer acquired somatic mutations and a lower frequency of high-risk mutations than their male counterparts; lower JAK2V617F driver variant allele frequency and attenuated allele burden kinetics have also been reported. Women with MPN are younger at diagnosis than men and, contingent on subtype, display more indolent disease features. Importantly, validated symptom burden assessments consistently disclose higher scores in women vs. men.

THROMBOSIS AND OUTCOMES

Women with MPN have a unique thrombotic diathesis with respect to men, more frequently involving the splanchnic venous system in those ultimately diagnosed with PV. Outcomes data depict female sex as a variable associated with more favorable clinical trajectories, including lower rates of MF/leukemic transformation and secondary cancers, as well as improved overall survival rates vis-à-vis men.

LIFE-CYCLE WINDOWS, PREGNANCY, AND POSTPARTUM

Potential challenges at each significant life stage will be addressed: puberty, preconception and fertility, and perimenopause; these include issues surrounding oral contraceptives and hormone use. Prospective studies suggest overall favorable maternal and fetal outcomes with pregnancy in women with MPN. Full details on risks and reported outcomes will be discussed, as well as a risk-adapted approach to management informed by obstetric and thrombosis history. Recommendations include aspirin 81 mg daily in all patients and cytoreduction with interferon-α in those with antecedent thrombosis, as well as in low-risk cases with higher-risk features (e.g., poorly controlled hematocrit and recurrent fetal loss). Antepartum anticoagulation with low molecular weight heparin (LMWH) is recommended in cases with previous venous thromboembolism.

CONCLUSIONS AND FUTURE DIRECTIONS

This review highlights female sex and gender as critical drivers of MPN incidence, presentation, and natural history. It further outlines the impact and management of MPN as related to unique female reproductive phases. A sex-informed lens will be required in order to recalibrate current prognostic tools, a requisite to refining patient counselling and clinical decision-making in line with precision medicine. Moreover, while several mechanisms underpinning sex-defined discrepancies have been defined, these mandate further prospective study. Finally, sex and gender-based differences must be weighted in clinical trials with systematized procedures to correct participation imbalances in favor of sex and gender equity.

Management of Bleeding, Thrombotic and Pregnancy-Related Complications in Women with Myeloproliferative Neoplasms: A Case-Based Review Focusing on Sex-Specific Challenges

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of clonal hematopoietic disorders that pose unique challenges in women, particularly regarding thrombosis, bleeding, fertility, and pregnancy. Women with MPN exhibit distinct thrombotic and sometimes contradictory bleeding profiles, including a higher prevalence of unusual thrombosis such as cerebral and splanchnic vein thrombosis and increased risk of hemorrhage from anti-thrombotic medication, acquired von Willebrand syndrome and platelet dysfunction. Estrogen-containing contraceptives should generally be avoided due to thrombotic risk. Around 10-20% of newly diagnosed MPN cases are women of childbearing age and the number is increasing annually. MPN patients when compared to controls have a lower rate of live birth rate of 71% vs. 80% with a hazard ratio of 0.78 (95% CI: 0.68-0.90), and increased preterm birth (14% vs. 4%), low birth weight (<2500 g, 10% vs. 4%), and increased cesarean section rate (32% vs. 17%). Management of MPN-related pregnancy requires specific considerations regarding the prevention of thrombosis, bleeding, and pregnancy-related complications. Management strategies during pregnancy include low-dose aspirin and consideration of low-molecular-weight heparin and interferon. Despite these challenges, most women with MPN can achieve successful pregnancies with optimized care. In this case-based review, we present two cases that illustrate key aspects of managing MPN in women, summarize the current literature, and propose a diagnostic and management framework tailored to these complexities.

Pregnancy: MPN management before, during, and after pregnancy

The aging obstetric population, combined with more frequent myeloproliferative neoplasm (MPN) diagnoses in younger patients, will result in hematologic providers increasingly caring for MPN patients in pregnancy. There are special considerations that pertain to management of pregnancy in MPN patients. This includes increased risks of thrombosis and hemorrhage as well as pregnancy complications that are likely related to placental dysfunction associated with an MPN diagnosis, including preeclampsia, preterm delivery, and intrauterine growth restriction. Complicating these outcomes is the uncertainty of the safety of many commonly used drugs in MPNs in pregnancy and breastfeeding. Given the overall low incidence of pregnancy in MPNs, many guidelines are based on expert opinions and extrapolation from other high-risk pregnancy populations. In this case-based review, we summarize the literature on MPN pregnancy outcomes and synthesize recommendations to provide guidance on the antepartum and postpartum management of MPN patients. Special attention is also made to issues relevant to preconception, including fertility and the use of assisted reproductive technology.

A comparative retrospective study of pre-fibrotic primary myelofibrosis versus overtly fibrotic stage in Qatar: clinicopathological, genetic landscape, risk stratification and survival data (2008-2021) - a single center experience

BACKGROUND

In MENA region, there is a lack of evidence on Primary Myelofibrosis (PMF), leading to its underrepresentation in medical literature. This study marks the first comprehensive report on PMF data in Qatar, presenting findings from a single-center study spanning 13 years (2008-2021).

METHODS

Clinicopathological data, genetic features, and disease progression parameters of pre-PMF and overt PMF subgroups were collected. Overall survival (OS), progression-free survival (PFS), DIPSS plus four categories and merged low and high-risk DIPSS scoring groups were assessed.

RESULTS

Pre-PMF patients showed higher hemoglobin (P < 0.001), and platelet counts (P < 0.05) but lower blast counts, LDH levels, constitutional symptoms (P < 0.0001), and splenomegaly (P < 0.010) than overt PMF patients. JAK2 V617F mutation was more common in pre-PMF (P = 0.059), while unfavorable karyotypes were exclusive to overt PMF (P = 0.028). Median overall survival was significantly longer at 276.9 months (IQR: 315.9, 276.9 months) to what was previously reported. Overt PMF patients predominantly fell into the higher DIPSS risk category (P < 0.001) and showed greater disease progression than pre-PMF (P < 0.0001). Complications including refractory anaemia (P < 0.001) and leukemic transformation (P = 0.043), increased notably in the high-risk group. Furthermore, 86.2% of high-risk patients required treatment versus 59.4% of the lower-risk group (P = 0.020).

CONCLUSIONS

To the best of our knowledge our research represents the first and largest published dataset on PMF in MENA region to be published. Merged DIPSS plus scoring came to be a pragmatic tool for defining high-risk patients who significantly differ in mortality, progression, need for treatment and leukemic transformation.

Aspirin therapy is associated with a lower risk of pregnancy loss in both JAK2- and CALR-mutated essential thrombocythemia-A Mayo Clinic study of 200 pregnancies

Two-hundred pregnancies involving 100 women with essential thrombocythemia (ET) were accessed from Mayo Clinic databases (1990-2023). Median platelet count displayed a decline during pregnancy, nadiring at 48% of baseline, in the third trimester: 704-369 × 109/L. Live birth rate was 72%. Of 53 (27%) unintentional pregnancy losses, 48 (24%) occurred in the first trimester. Other fetal complications included preterm birth 3%, intrauterine growth retardation 3%, and stillbirth 1%. Maternal complications included major hemorrhage (7%), preeclampsia (6%), thrombosis (1%), and placental abruption (0.5%). Antepartum management included no specific therapy in 52 (26%), aspirin alone in 112 (56%), aspirin combined with cytoreductive drugs or systemic anticoagulants in 23 (12%), and other permutations in the remaining. Postpartum systemic anticoagulation was documented in 29 (15%) pregnancies. Unintentional first-trimester loss was predicted by prior fetal loss (43% vs. 18%; p < .01), diabetes mellitus (DM; 67% vs. 23%; p = .02), and absence of aspirin therapy (45% vs. 14%; p < .01); the salutary effect of aspirin therapy was independent of the other two risk factors and apparent in both high (presence of ≥1 risk factor; 33% vs. 61%; p = .07) and low (absence of both risk factors; 10% vs. 34%; p < .01) risk scenarios. The benefit of aspirin therapy, in preventing first-trimester loss, was significant in both JAK2-mutated (18% vs. 50%; p < .01) and CALR-mutated (8% vs. 43%; p < .01) cases. Aspirin use was also associated with a lower risk of venous thrombosis (0% vs. 3%; p = .03). By contrast, the use of systemic anticoagulation, antepartum or postpartum, did not influence fetal or maternal complication rates. CALR mutation and DM predicted maternal hemorrhage (13% vs. 4%; p = .05) and preeclampsia (33% vs. 5%; p = .03), respectively. The current study demonstrates the protective role of aspirin in preventing first-trimester loss in ET, independent of driver mutation status or other risk factors.

Myeloproliferative neoplasms in the adolescent and young adult population: A comprehensive review of the literature

Myeloproliferative neoplasms (MPN) are characterized by a clonal proliferation of myeloid lineage cells within the bone marrow. The classical BCR-ABL negative MPNs are comprised of polycythaemia vera, essential thrombocythaemia and primary myelofibrosis. Historically, the majority of MPNs are diagnosed in adults older than 60 years of age; however, in recent years, there has been recognition of MPNs in the adolescent and young adult (AYA) population. AYAs with MPN, typically defined as between the ages of 15 and 39 years old, may comprise up to 20% of patients diagnosed with MPN. They demonstrate unique patterns of driver mutations and thrombotic events and remain at risk for progression to more aggressive disease states. Given the likely long length of time they will live with their disease, there is a significant unmet need in identifying well-tolerated and effective treatment options for these patients, particularly with the advent of disease modification. In this review, we provide a comprehensive overview of the clinical features, disease course and management of AYA patients with MPN and, in doing so, highlight key characteristics that distinguish them from their older counterparts.

Childbirth rates in women with myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are associated with inferior pregnancy outcome, however, little is known about fertility and childbearing potential in women with MPN. In this study we aimed to describe reproductive patterns, as well as to quantify risk of miscarriage and stillbirth. Women aged 15-44 years with an MPN diagnosis 1973-2018, were identified in Swedish health care registers, and age-matched 1:4 to population controls. We identified 1141 women with MPN and 4564 controls. Women with MPN had a lower rate of childbirth (hazard ratio [HR] with 95% confidence interval was 0.78 (0.68-0.90)). Subgroup analysis showed that the rate was not significantly reduced in essential thrombocythemia, HR 1.02 (0.86-1.22) while the HR was 0.50 (0.33-0.76) in PV and 0.45 (0.28-0.74) in PMF. The risk of miscarriage was not significantly increased before MPN diagnosis, the HR during follow-up after diagnosis was 1.25 (0.89-1.76). Women with MPN were more likely to have had a previous stillbirth. Women with MPN had fewer children at diagnosis, and fewer children in total. In conclusion, the childbirth rate was lower among women with MPN than controls, but not among women with essential thrombocythemia.

Essential thrombocythemia: 2024 update on diagnosis, risk stratification, and management

OVERVIEW

Essential thrombocythemia is a Janus kinase 2 (JAK2) mutation-prevalent myeloproliferative neoplasm characterized by clonal thrombocytosis; clinical course is often indolent but might be interrupted by thrombotic or hemorrhagic complications, microcirculatory symptoms (e.g., headaches, lightheadedness, and acral paresthesias), and, less frequently, by disease transformation into myelofibrosis (MF) or acute myeloid leukemia.

DIAGNOSIS

In addition to thrombocytosis (platelets ≥450 × 109 /L), formal diagnosis requires the exclusion of other myeloid neoplasms, including prefibrotic MF, polycythemia vera, chronic myeloid leukemia, and myelodysplastic syndromes with ring sideroblasts and thrombocytosis. Bone marrow morphology typically shows increased number of mature-appearing megakaryocytes distributed in loose clusters.

GENETICS

Approximately 80% of patients express myeloproliferative neoplasm driver mutations (JAK2, CALR, MPL), in a mutually exclusive manner; in addition, about 50% harbor other mutations, the most frequent being TET2 (9%-11%), ASXL1 (7%-20%), DNMT3A (7%), and SF3B1 (5%). Abnormal karyotype is seen in <10% of patients and includes +9/20q-/13q-.

SURVIVAL AND PROGNOSIS

Life expectancy is less than that of the control population. Median survival is approximately 18 years but exceeds >35 years in younger patients. The triple A survival risk model, based on Age, Absolute neutrophil count, and Absolute lymphocyte count, effectively delineates high-, intermediate-1-, intermediate-2-, and low-risk disease with corresponding median survivals of 8, 14, 21, and 47 years.

RISK FACTORS FOR THROMBOSIS

Four risk categories are considered: very low (age ≤60 years, no thrombosis history, JAK2 wild-type), low (same as very low but JAK2 mutation present), intermediate (same as low but age >60 years), and high (thrombosis history or age >60 years with JAK2 mutation).

MUTATIONS AND PROGNOSIS

MPL and CALR-1 mutations have been associated with increased risk of MF transformation; spliceosome with inferior overall and MF-free survival; TP53 with leukemic transformation, and JAK2V617F with thrombosis. Leukemic transformation rate at 10 years is <1% but might be higher in JAK2-mutated patients with extreme thrombocytosis and those with abnormal karyotype.

TREATMENT

The main goal of therapy is to prevent thrombosis. In this regard, once-daily low-dose aspirin is advised for all patients and twice daily for low-risk disease. Cytoreductive therapy is advised for high-risk and optional for intermediate-risk disease. First-line cytoreductive drugs of choice are hydroxyurea and pegylated interferon-α and second-line busulfan.

ADDITIONAL CONTENT

The current review includes specific treatment strategies in the context of extreme thrombocytosis, pregnancy, splanchnic vein thrombosis, perioperative care, and post-essential thrombocythemia MF, as well as new investigational drugs.

How I treat myeloproliferative neoplasms in pregnancy

ABSTRACT

Although myeloproliferative neoplasms (MPNs) are traditionally considered diseases of adults in their sixth or seventh decade, these conditions do occur in young patients; for example, for essential thrombocythemia, in particular, there is a second peak in women of reproductive age. Therefore, pregnancy is an uncommon but not rare occurrence and clinical challenge in some scenarios. Here, we discuss in detail our local approach to the management of pregnancy in patients with MPN while taking a case-based approach. We include relevant updates in the field and point to a future research strategy that should be internationally focused to obtain as much information in as short a time as possible.

Essential Thrombocythemia in Adolescents and Young Adults: Clinical Aspects, Treatment Options and Unmet Medical Needs

OPINION STATEMENT

Current treatment of essential thrombocythemia (ET) should primarily prevent thrombo-hemorrhagic events, without increasing the rate of fibrotic progression or leukemic evolution, and secondarily control microvascular symptoms. Unlike other classic BCR::ABL1-negative myeloproliferative neoplasms, ET is frequently diagnosed in adolescents and young adults (AYA), defined as individuals aged 15 to 39 years, in up to 20% of patients. However, since the current risk stratification of this disease is based on models, including that of ELN, IPSET-Thrombosis and its revised version, mainly applied to an older patients' population, international guidelines are needed that specifically consider how to evaluate the prognosis of AYAs with ET. Furthermore, although ET is the most frequent MPN among AYA subjects, there is a lack of specific recommendations on how to treat it in this subgroup of patients, as management decisions are typically extrapolated from those for the elderly. Accordingly, since AYAs with ET represent a unique disease subset defined by attenuated genetic risk, more indolent phenotype, and longer survival than their older counterparts, treatment selection requires special attention to specific issues such as the risk of fibrotic/leukemic transformation, carcinogenicity, and fertility. This review article will provide a comprehensive overview of the diagnosis, prognostic stratification, and possible therapeutic approaches for AYA patients with ET, including antiplatelets/anticoagulants and cytoreductive agents, with a focus on pregnancy management in real-life clinical practice.

A Case Report of Ropeginterferon Alfa-2b for Polycythemia Vera during Pregnancy

Myeloproliferative neoplasms (MPN) such as essential thrombocythemia (ET) and polycythemia vera (PV) are rare during pregnancy. However, they are harmful because they are associated with an increased risk of thromboembolic, hemorrhagic, or microcirculatory disturbances or placental dysfunction leading to fetal growth restriction or loss. Low-dose aspirin and low-molecular-weight heparin (LMWH) are recommended to reduce pregnancy complications, and interferon (IFN) is the only treatment option for cytoreductive therapy based on the likelihood of live birth in pregnant women with MPN. Since ropeginterferon alfa-2b is the only available IFN in South Korea, we present a case report of ropeginterferon alfa-2b use during pregnancy in an MPN patient. A 40-year-old woman who had been diagnosed with low-risk PV in 2017 and had been maintained on phlebotomy, hydroxyurea (HU), and anagrelide (ANA) for 4 years was confirmed as 5 weeks pregnant on 9 December 2021. After stopping treatment with HU and ANA, the patient showed a rapid increase in platelet count (1113 × 109/L to 2074 × 109/L, normal range, 150–450 × 109/L) and white blood cell count (21.93 × 109/L to 35.55 × 109/L, normal range, 4.0–10.0 × 109/L). Considering the high risk of complications, aggressive cytoreductive treatment was required, for which we chose ropeginterferon alfa-2b, as it is the only available IFN agent in South Korea. The patient underwent 8 cycles of ropeginterferon alfa-2b over 6 months during pregnancy and delivered without any neonatal or maternal complications. This case report highlights the importance of considering treatment options for MPN patients who are pregnant or planning a pregnancy, as well as the need for further investigation into the safety and efficacy of ropeginterferon alfa-2b in this population.

Impact of mutations on pregnancy outcome in patients with myeloproliferative neoplasms

The impact of driver and other somatic mutations on pregnancy outcomes is unknown. The purpose of this study was to report the management and outcome of pregnancies in a cohort of myeloproliferative neoplasms (MPN) patients, particularly to evaluate the impact of somatic mutations. The cohort included consecutive patients with MPN who had a least one confirmed pregnancy. The primary outcome was live births. Secondary outcomes were thrombotic and major bleeding events. Between 2010 and 2021, 29 pregnancies occurred in 24 individuals with MPN. Aspirin was used in 24 cases (83%) and interferon alfa in five (17%). There were 24 live births (83%). There were three thrombotic events, two antepartum and one postpartum. Miscarriages and thrombotic events occurred in JAK2-mutated and triple negative, but not CALR-mutated, MPN. Additional somatic mutations were rare, and there were no apparent associations with pregnancy loss or complications. While JAK2 V617F is associated with an increased risk of thrombosis, its impact on pregnancy outcome has been inconsistently reported. The association between triple negative MPN and adverse pregnancy outcome has not previously been reported. While limited by small numbers, this study underscores the importance of describing driver and other mutations to direct optimal antenatal care in individuals with MPN.

Portal Vein Thrombosis after C-Section in a Patient with Polycythemia Vera (PV) Due to Pregnancy and Iron Deficiency Anemia (IDA)

Polycythemia vera (PV) is one of the three main classic disorders of Philadelphia-negative myeloproliferative neoplasms (MPNs), with the other two being essential thrombocythemia (ET) and primary myelofibrosis (PMF). PV may develop (15%) in women of childbearing age (15-45 years), with an anticipated rate of roughly 0.3 per 100,000 people, although maintaining a male to female ratio predominance of about 2:1 and a peak prevalence in the sixth and seventh decades of life. Without always being presented with its actual clinical manifestations due to pregnancy itself, and most commonly due to iron deficiency, PV can be frequently missed and therefore belatedly diagnosed. We describe the case of a primipara woman in her 40s, without risk factors for thrombosis, who developed a portal vein occlusion 1.5 month postpartum after C-section and who had a delayed diagnosis of PV.

Pregnancy and childbirth outcomes in women with myeloproliferative neoplasms-a nationwide population-based study of 342 pregnancies in Sweden

Pregnancy and childbirth in women with myeloproliferative neoplasms (MPN) are reported to be associated with maternal thrombosis, hemorrhage, and placental dysfunction. To assess the risks of adverse events in pregnancy in women with MPN, we performed a large population-based study using Swedish health care registers, and included all pregnancies that had reached gestational week 22 (prior to 2008, week 28) during the years 1973-2017 in women with MPN. Control pregnancies were matched 1:1 for age, calendar year, and parity. We identified 342 pregnancies in 229 women with MPN. Preterm birth was significantly increased in pregnancies in MPN, 14% compared to 4% of pregnancies in controls (p < 0.001). Correspondingly, low birth weight (<2500 g) was also significantly increased in MPN pregnancies (p = 0.042). Stillbirth was rare, with two events (0.6%) in MPN, none in controls. Maternal thrombotic complications occurred in three (1%) of the pregnancies in MPN patients, compared to none in controls. Pregnancy-related bleeding affected 14% of pregnancies in MPN and 9% in controls (p < 0.110). Cesarean section was significantly more common in pregnancies in MPN. Incidence was 12.2 per 100.000 pregnancies. In summary, preterm birth was an important complication in MPN pregnancies, while maternal complications were less common than previously reported.

Illustrated State-of-the-Art Capsules of the ISTH 2022 Congress

The ISTH London 2022 Congress is the first held (mostly) face-to-face again since the COVID-19 pandemic took the world by surprise in 2020. For 2 years we met virtually, but this year's in-person format will allow the ever-so-important and quintessential creativity and networking to flow again. What a pleasure and joy to be able to see everyone! Importantly, all conference proceedings are also streamed (and available recorded) online for those unable to travel on this occasion. This ensures no one misses out. The 2022 scientific program highlights new developments in hemophilia and its treatment, acquired and other inherited bleeding disorders, thromboinflammation, platelets and coagulation, clot structure and composition, fibrinolysis, vascular biology, venous thromboembolism, women's health, arterial thrombosis, pediatrics, COVID-related thrombosis, vaccine-induced thrombocytopenia with thrombosis, and omics and diagnostics. These areas are elegantly reviewed in this Illustrated Review article. The Illustrated Review is a highlight of the ISTH Congress. The format lends itself very well to explaining the science, and the collection of beautiful graphical summaries of recent developments in the field are stunning and self-explanatory. This clever and effective way to communicate research is revolutionary and different from traditional formats. We hope you enjoy this article and will be inspired by its content to generate new research ideas.

Treatment options and pregnancy management for patients with PV and ET

Polycythemia vera (PV) and essential thrombocythemia (ET) are the two most common subtypes of Philadelphia chromosome-negative myeloproliferative neoplasm (MPN). PV results in erythrocytosis and ET in thrombocytosis. The discovery of JAK2 mutations in the majority of patients with MPN over the last 2 decades has led to the development of JAK inhibitors. Because PV and ET progress relatively slowly, the main treatment strategy for these two diseases is to prevent thrombotic complications. The first-line agent for both PV and ET is hydroxyurea, although some patients are intolerant or refractory to this compound and need other treatment options. Notably, hydroxyurea is contraindicated during pregnancy. In addition to JAK inhibitors, several new agents, such as HDAC inhibitors, LSD1 inhibitors, MDM2 inhibitors and hepcidin mimetics, have been developed as treatment options. Classical agents, such as busulfan and interferon, are still used to treat patients with PV or ET as well. Based on this context, treatment options and pregnancy management for patients with PV or ET are discussed in this review.

Management of Myeloproliferative Neoplasms (MPNs)

PURPOSE

To provide up to date guidance, practice recommendations and highlight barriers to medication adherence in the long-term management of chronic myeloproliferative neoplasms (MPNs).

AIM

Current drug therapy for MPN is not curative and has not been shown to prolong survival. The main indication for treatment is the prevention of thrombosis and medication adherence remains a challenge in this group of patients. Identifying potentially modifiable barriers to medication adherence including primary nonadherence and non-persistent adherence enables timely interventions to be put in place and improve overall medication adherence.

METHODS

A systematic review of peer-reviewed literature and expert opinions was performed using electronic databases (PubMed, EMBASE, MEDLINE, and Web of Science) that were searched for articles reporting MPN and medication adherence. Discussions A case vignette is discussed throughout the article and expert opinion with international peer reviewed guidelines that are authored to support clinical decision making at the point of care were utilised. The evidence base was combined with more practical/clinical (data based) insight from real world clinical practice. Adoption of a broad range of digital health care activities and services in the health care system (telehealth applications) by the advanced practice providers (Non-Medical Prescribers-NMPs) in MPN clinics included medication prescribing and management, oral drug compliance and adherence evaluations, interventions, chronic care management, counselling and patient education on treatments.

CONCLUSION

Current drug therapy for MPN is neither curative nor has it been shown to prolong survival, and medication adherence remains a challenge in this group of patients. The longevity of the patients' disease course may contribute to the high risk of non-adherence in this patient cohort. Poor adherence to long-term therapies severely compromises the effectiveness of treatment. Adherence interventions should be tailored to the needs of the patient in order to achieve maximum impact. Interventions aimed at improving adherence provide the best experience and outcome for the patient and their families and can have a profound impact on the quality of life and mitigation of disease consequences.

How I manage myeloproliferative neoplasm-unclassifiable: Practical approaches for 2022 and beyond

Myeloproliferative neoplasm (MPN)-unclassifiable (MPN-U) or not otherwise specified represents a rare, poorly defined and heterogeneous group of MPNs. Disease incidence is difficult to define but likely represents close to 5% of all MPNs when strict World Health Organisation (WHO) criteria are applied. Dynamic review over time is required to assess if the disease can be re-classified into another MPN entity. A diagnosis of MPN-U leads to many challenges for both the patient and physician alike including lack of agreed monitoring and therapeutic guidelines, validated prognostic markers and licenced therapies coupled with exclusion from clinical trials. MPN-U has an inherent risk of an aggressive clinical course and transformation in some but who, and when to treat in the chronic phase, including identifying who may require more aggressive therapy at an earlier stage, remains elusive. Moreover, despite the significant thrombotic risk, there is no agreement on systematic primary thromboprophylaxis. We hereby provide a contemporary overview of MPN-U in addition to four illustrative cases providing our collective suggested approaches to clinical challenges.

Thrombotic and Hemorrhagic Issues Associated with Myeloproliferative Neoplasms

Thrombotic and hemorrhagic complications are related to a significant rate of morbidity and mortality in patients with myeloproliferative neoplasms (MPNs), they are therefore called “thrombohemorrhagic” syndromes. Several clinical factors, such as age and presence of cardiovascular comorbidities are responsible for thrombotic complications. High blood counts, platelet alterations, presence of JAK2 mutation and possibly of other CHIP mutations such as TET2, DNMT3A, and ASXL1, procoagulant microparticles, NETs formation, endothelial activation and neo-angiogenesis are some of the parameters accounting for hypercoagulability in patients with myeloproliferative neoplasms. Bleeding complications emerge as a result of platelet exhaustion. They can be also linked to a functional deficiency of von Willebrand factor, when platelet counts rise above 1000G/L. The mainstay of management consists on preventing hemostatic complications, by antiplatelet and/or anticoagulant treatment and myelosuppressive agents in high-risk patients.Circumstances related to a high thrombohemorrhagic risk, such as pregnancy and the perioperative period, prompt for specific management with regards to anticoagulation and myelosuppression treatment type. In order to apply a patient-specific treatment strategy, there is a need for a risk score assessment tool encompassing clinical parameters and hemostasis biomarkers.

Is It Possible to Predict Clonal Thrombocytosis in Triple-Negative Patients with Isolated Thrombocytosis Based Only on Clinical or Blood Findings?

JAK2, MPL, and CALR mutations define clonal thrombocytosis in about 90% of patients with sustained isolated thrombocytosis. In the remainder of patients (triple-negative patients) diagnosing clonal thrombocytosis is especially difficult due to the different underlying conditions and possible inconclusive bone marrow biopsy results. The ability to predict patients with sustained isolated thrombocytosis with a potential clonal origin has a prognostic value and warrants further examination. The aim of our study was to define a non-invasive clinical or blood parameter that could help predict clonal thrombocytosis in triple-negative patients. We studied 237 JAK2 V617-negative patients who were diagnosed with isolated thrombocytosis and referred to the haematology service. Sixteen routine clinical and blood parameters were included in the logistic regression model which was used to predict the type of thrombocytosis (reactive/clonal). Platelet count and lactate dehydrogenase (LDH) were the only statistically significant predictors of clonal thrombocytosis. The platelet count threshold for the most accurate prediction of clonal or reactive thrombocytosis was 449 × 10⁹/L. Other tested clinical and blood parameters were not statistically significant predictors of clonal thrombocytosis. The level of LDH was significantly higher in CALR-positive patients compared to CALR-negative patients. We did not identify any new clinical or blood parameters that could distinguish clonal from reactive thrombocytosis. When diagnosing clonal thrombocytosis triple-negative patients are most likely to be misdiagnosed. Treatment in patients with suspected triple negative clonal thrombocytosis should not be delayed if cardiovascular risk factors or pregnancy coexist, even in the absence of firm diagnostic criteria. In those cases the approach “better treat more than less” should be followed.

Philadelphia chromosome-negative myeloproliferative neoplasms in younger adults: A critical discussion of unmet medical needs, with a focus on pregnancy

Myeloproliferative neoplasms (MPN) are traditionally regarded as a disease of older adults, though a not negligible fraction of cases occurs at a younger age, including women of childbearing potential. MPN in younger patients, indeed, offer several challenges for the clinical hematologist, that goes from difficulties in reaching a timely and accurate diagnosis to a peculiar thrombotic risk, with a relatively high incidence of thromboses in unusual sites (as the splanchnic veins or the cerebral ones). Moreover, the issue of pregnancy is recently gaining more attention as maternal age is rising and molecular screening are widely implemented, leading to a better recognition of these cases, both before and during pregnancy. In the present work we aim at discussing four clinical topic that we identified as areas of uncertainty or true unmet medical needs in the management of younger patients with MPN, with a particular focus on the topic of pregnancy. For each of these topics, we critically reviewed the available evidence that support treatment decisions, though acknowledging that recommendations in this field are mostly based on expert opinion or derived from guidelines of other clinical conditions that share with MPN a high vascular risk, as antiphospholipid syndrome. Taking into consideration both the lack of evidence-based data and the clinical heterogeneity of MPN, we support an individualized strategy of counseling and management for both young patients and for expectant mother with MPN.

Management Issues and Controversies in Low-Risk Patients with Essential Thrombocythemia and Polycythemia Vera

PURPOSE OF REVIEW

Essential thrombocythemia (ET) and polycythemia vera (PV) are the most common myeloproliferative neoplasms (MPNs). Treatment of ET and PV is based on the risk for subsequent thrombosis. High-risk patients, defined as older than 60, JAK2 V617F-positive patients, or patients with a history of prior thrombosis, merit cytoreduction to control blood counts, whereas a watchful waiting paradigm is utilized in low-risk patients. However, low-risk patients have a host of other specific management issues that arise during their disease course. This review will discuss the most common management issues specific to the care of low-risk patients, including anti-platelet therapy dosing, pregnancy, and indications for early cytoreduction.

RECENT FINDINGS

Although low-dose aspirin is well established in PV, its indications and dosing regimens are less clear in ET. Recent evidence has supported twice daily low-dose aspirin in ET and observation alone in very low-risk ET patients. Pregnancy is not contraindicated in MPNs, and we recommend aspirin throughout pregnancy with consideration for prophylactic postpartum anticoagulation. High phlebotomy needs, symptom burden, and extreme thrombocytosis are common reasons for initiation of cytoreduction in low-risk patients, although we typically do not start cytoreduction for an isolated high platelet count alone. Recent data has also demonstrated a potential disease-modifying effect of interferons in MPNs, with some experts now advocating the early use of interferon in low-risk patients, although more mature data is needed before practice guidelines change. We evaluate the literature to inform clinical decision-making regarding these controversies, including most recent data that has challenged the "watchful waiting" paradigm. Our discussion provides guidance on common clinical scenarios seen in low-risk ET and PV patients, who face a myriad of complex management decisions in their care.

Essential Thrombocythemia in a 15-Year-Old Female: Presentation, Workup, and Treatment Considerations in the Pediatric Population

Essential thrombocythemia (ET) is a diagnosis most often seen in adults but can also present in children in rare cases. This article reviews the presentation, diagnosis, and treatment of ET in a 15-year-old female followed by a review of the literature regarding special considerations in the workup, diagnosis, treatment, and follow-up of ET in the pediatric population.

The management, outcome, and postpartum disease course of 41 pregnancies in 20 women with polycythemia vera

OBJECTIVES

Pregnancies in women with polycythemia vera (PV) are associated with an increased risk of PV-related maternal complications and often result in miscarriage. Recommendations for the management of PV pregnancies are mainly based on studies with a small number of patients. A correlation between pregnancy outcome and postpartum course has been reported for essential thrombocythemia, but corresponding data for PV are lacking so far.

METHODS

In 41 PV pregnancies, the pregnancy outcome, the use of PV-specific therapies (ie, acetylsalicylic acid, low-molecular weight heparin and/or interferon-alpha), and the postpartum PV course were investigated.

RESULTS

A live birth rate of 51.2% (21/41 pregnancies) was observed. 43.9% of pregnancies ended in spontaneous abortion and 4.9% in stillbirth. A significantly increased live birth rate occurred in pregnancies with PV-specific therapies compared to standard antenatal care (69.0% vs. 8.3%; P < .0019). The use of PV-specific therapy significantly increased the number of maternal hemorrhages (P = .021) without increasing the risk of fetal complications. During the median postpartum follow-up period of 1.2 years (range 0.1-13.7), complicated postpartum PV occurred significantly more often after miscarriages (P = .035).

CONCLUSIONS

According to our analysis, PV-specific therapy improved the live birth rate. Significantly more complicated postpartum PV courses were observed after miscarriages.

Myeloproliferative neoplasms and pregnancy: Overview and practice recommendations

Pregnancy in the context of myeloproliferative neoplasms (MPN) poses unique fetal and maternal challenges. Current literature in this regard mostly involves essential thrombocythemia (ET) and less so polycythemia vera (PV) or myelofibrosis. In ET, live birth rate is estimated at 70% with first trimester fetal loss (˜ 30%) as the major complication. Risk of pregnancy-associated complications is higher in PV, thus mandating a more aggressive treatment approach. Herein, we appraise the relevant literature, share our own experience and propose management recommendations. Aspirin therapy may offer protection against fetal loss; however the additive benefit of systemic anticoagulation or cytoreductive therapy, in the absence of high risk disease, is unclear. We recommend cytoreductive therapy in the form of interferon alpha in all high risk and select low-risk ET and PV patients with history of recurrent fetal loss, prominent splenomegaly or suboptimal hematocrit control with phlebotomy. In addition, all women with PV should maintain strict hematocrit control <45% with the aid of phlebotomy. Systemic anticoagulation with low molecular weight heparin is advised in patients with history of venous thrombosis. Further clarification awaits prospective clinical trials that implement risk adapted therapeutic interventions.

Low-Risk Essential Thrombocythemia: A Comprehensive Review

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by a persistently elevated platelet count in the absence of a secondary cause. The clinical consequences of uncontrolled thrombocytosis can include both thrombosis and hemorrhage. Patients with features conferring a “high risk” of vascular events benefit from reduction of the platelet count through cytoreductive therapy. The management of patients who lack such high-risk features has until recently been less well defined, but it is now apparent that many require minimal or even no intervention. In this review, we discuss the diagnostic pathway for younger patients with unexplained thrombocytosis, including screening molecular investigations, the role of bone marrow biopsy, and investigations in those patients negative for the classic myeloproliferative neoplasm driver mutations (JAK2, CALR, MPL). We discuss conventional and novel risk stratification methods in essential thrombocythemia and how these can be best applied in clinical practice, particularly in the era of more comprehensive genomic testing. The treatment approach for “low risk” patients is discussed including antiplatelets and the options for cytoreductive therapy, if indicated, together with areas of clinical need for future study.

Is there a gender effect in polycythemia vera?

In recent times, there has been a growing interest in understanding the impact of gender on disease biology and clinical outcomes in Philadelphia-negative chronic myeloproliferative neoplasms. Among those, polycythemia vera (PV) is characterized by increased thrombotic risk, systemic symptoms, and overall reduced survival. Here, we aim to summarize data on whether and to what extent female sex can affect PV biology and outcome. To this end, we will discuss the latest acquisitions in terms of pathogenesis, diagnosis, epidemiology, clinical presentation and symptoms burden, thrombotic risk and related treatment strategies, and prognosis in female patients affected by PV.

The 2020 revision of the guidelines for the management of myeloproliferative neoplasms

In 2016, the World Health Organization revised the diagnostic criteria for myeloproliferative neoplasms (MPNs) based on the discovery of disease-driving genetic aberrations and extensive analysis of the clinical characteristics of patients with MPNs. Recent studies have suggested that additional somatic mutations have a clinical impact on the prognosis of patients harboring these genetic abnormalities. Treatment strategies have also advanced with the introduction of JAK inhibitors, one of which has been approved for the treatment of patients with myelofibrosis and those with hydroxyurea-resistant or intolerant polycythemia vera. Recently developed drugs aim to elicit hematologic responses, as well as symptomatic and molecular responses, and the response criteria were refined accordingly. Based on these changes, we have revised the guidelines and present the diagnosis, treatment, and risk stratification of MPNs encountered in Korea.

The Essential Thrombocythemia in 2020: What We Know and Where We Still Have to Dig Deep

The Essential Thrombocythemia is a Chronic Philadelphia-negative Myeloproliferative Neoplasm characterized by a survival curve that is only slightly worse than that of age- and sex-adjusted healthy population. The criteria for diagnosis were reviewed in 2016 by WHO. The incidence varies from 0.2 to 2.5:100 000 people per year, with a prevalence of 38 to 57 cases per 100 000 people. The main characteristics of ET are the marked thrombocytosis and the high frequency of thrombosis. The spectrum of symptoms is quite wide, but fatigue results to be the most frequent. Thrombosis is frequently observed, often occurring before or at the time of diagnosis. The classification of thrombotic risk has undergone several revisions. Recently, the revised-IPSET-t has distinguished 4 risk classes, from very low risk to high risk. Driver mutations seem to influence thrombotic risk and prognosis, while the role of sub-driver mutations still remains uncertain. Antiplatelet therapy is recommended in all patients aged ⩾ 60 years and in those with a positive history of thrombosis or with cardiovascular risk factors, while cytoreductive therapy with hydroxyurea or interferon is reserved for high-risk patients.

Pregnancy outcomes, risk factors, and cell count trends in pregnant women with essential thrombocythemia

Pregnancy in essential thrombocythemia (ET) is associated with increased risk of obstetric complications. We retrospectively evaluated risk factors in 121 pregnancies in 52 ET women seen at 3 affiliate hospitals. Univariable and multivariable analyses were performed at the α = 0.10 level. Cell counts were characterized throughout pregnancy and correlated with outcomes using logistic modeling. The overall live birth rate was 69 %. 48.7 % of all women experienced a pregnancy complication, the most common being spontaneous abortion, which occurred in 26 % of all pregnancies. Maternal thrombosis and hemorrhage rates were 2.5 % and 5.8 %. On multivariable analysis, aspirin use (OR 0.29, p = 0.014, 90 % CI 0.118-0.658) and history of prior pregnancy loss (OR 3.86, p = 0.011, CI 1.49-9.15) were associated with decreased and increased pregnancy complications, respectively. A Markov model was used to analyze the probability of a future pregnancy complication based on initial pregnancy outcome. An ET woman who suffers a pregnancy complication has a 0.594 probability of a subsequent pregnancy complication, compared to a 0.367 probability if she didn't suffer a complication. However, despite this elevated risk, overall prognosis is good, with a >50 % probability of a successful pregnancy by the third attempt. Platelet counts decreased by 43 % in ET during pregnancy, with nadir at delivery and prompt recovery in the postpartum period. Women with larger declines in gestational platelet counts were less likely to suffer complications (p = 0.083). Our study provides important guidance to physicians treating ET women during pregnancy, including counseling information regarding risk assessment and expected trajectory of platelet levels.

A Young Woman with Thrombocytosis

The diagnostic approach to thrombocytosis involves consideration of reactive, hereditary, and neoplastic causes. Once reactive causes of thrombocytosis, such as iron deficiency, infections, solid tumors, and other obvious causes such as post-splenectomy thrombocytosis, have been ruled out, the focus shifts to myeloid malignancies, such as chronic myeloid leukemia (CML), the classic Philadelphia chromosome-negative (Ph^-) myeloproliferative neoplasms (MPNs), essential thrombocythemia (ET), primary myelofibrosis (PMF), polycythemia vera (PV), myelodysplastic syndrome (MDS) with isolated deletion 5q and the rare MDS/MPN "overlap" syndrome, MDS/MPN with ring sideroblasts, and thrombocytosis (MDS/MPN-RS-T).

From Budd-Chiari syndrome to acquired von Willebrand syndrome: thrombosis and bleeding complications in the myeloproliferative neoplasms

Thrombotic and hemorrhagic complications are prevalent in patients with essential thrombocythemia, polycythemia vera, and myelofibrosis. Given the impact on morbidity and mortality, reducing the risk of thrombosis and/or hemorrhage is a major therapeutic goal. Historically, patients have been risk stratified on the basis of traditional factors, such as advanced age and thrombosis history. However, multiple factors contribute to the thrombotic tendency, including gender, mutational profile, inflammatory stress, and abnormal cell adhesion. Management includes cardiovascular risk reduction and use of antiplatelet therapy, depending on myeloproliferative neoplasm subtype and mutational status. Anticoagulation is a mainstay of therapy for those with venous thrombosis, but practice patterns remain heterogeneous. Cytoreduction is indicated for higher-risk patients, but efficacy may depend on the involved vascular bed. Management of special situations, such as unusual site thrombosis, bleeding, the perioperative period, and pregnancy, are especially challenging. In this article, risk factors and treatment strategies for myeloproliferative neoplasm thrombosis and bleeding, including special situations, are reviewed. Insights gained from recent studies may lead to the development of a more precise risk classification and tailored therapy.

How we manage Philadelphia-negative myeloproliferative neoplasms in pregnancy

The combined incidence of classical Philadelphia-negative myeloproliferative neoplasm (MPN) is 6-9/100 000 with a peak frequency between 50 and 70 years. MPN is less frequent in women of reproductive age. However, for essential thrombocythaemia (ET) in particular there is a second peak in women of reproductive age and 15% of polycythaemia vera (PV) patients are less than 40 years of age at the time of diagnosis. Thus these diseases are encountered in women of reproductive potential and may be diagnosed in pregnancy or in women being investigated for recurrent pregnancy loss. The incidence of MPN pregnancies is 3·2/100 000 maternities per year in the UK. The majority of data regarding Philadelphia-negative MPNs relates to patients with ET, for which the literature suggests significant maternal morbidity and poor fetal outcome; specifically maternal thrombosis and haemorrhage, miscarriage, pre-eclampsia, intrauterine growth restriction (IUGR), stillbirth and premature delivery as summarised in the recent systematic review and meta-analysis in Blood, 2018, 132, 3046. The literature for PV is more sparse but increasing and is concordant with ET pregnancy outcomes. The literature regarding primary myelofibrosis (PMF) is even more scarce. Treatment options include aspirin, venesection, low molecular weight heparin (LMWH) and cytoreductive therapy. Data and management recommendations are often extrapolated from other pro-thrombotic conditions or from ET to PV and PMF. Women of reproductive age with a diagnosis of MPN should receive information and assurance regarding management and outcome of future pregnancies. From pre-conceptual planning to the post-partum period, women should have access to joint care from an obstetrician with experience of high-risk pregnancies and a haematologist in a multidisciplinary setting. This paper provides an update with regards to Philadelphia-negative MPN in pregnancy, details local practise in an internationally recognised centre for patients with MPN and outlines a future research strategy.

From Budd-Chiari syndrome to acquired von Willebrand syndrome: thrombosis and bleeding complications in the myeloproliferative neoplasms

Thrombotic and hemorrhagic complications are prevalent in patients with essential thrombocythemia, polycythemia vera, and myelofibrosis. Given the impact on morbidity and mortality, reducing the risk of thrombosis and/or hemorrhage is a major therapeutic goal. Historically, patients have been risk stratified on the basis of traditional factors, such as advanced age and thrombosis history. However, multiple factors contribute to the thrombotic tendency, including gender, mutational profile, inflammatory stress, and abnormal cell adhesion. Management includes cardiovascular risk reduction and use of antiplatelet therapy, depending on myeloproliferative neoplasm subtype and mutational status. Anticoagulation is a mainstay of therapy for those with venous thrombosis, but practice patterns remain heterogeneous. Cytoreduction is indicated for higher-risk patients, but efficacy may depend on the involved vascular bed. Management of special situations, such as unusual site thrombosis, bleeding, the perioperative period, and pregnancy, are especially challenging. In this article, risk factors and treatment strategies for myeloproliferative neoplasm thrombosis and bleeding, including special situations, are reviewed. Insights gained from recent studies may lead to the development of a more precise risk classification and tailored therapy.

Association of Treatments for Myeloproliferative Neoplasms During Pregnancy With Birth Rates and Maternal Outcomes: A Systematic Review and Meta-analysis

Importance

Myeloproliferative neoplasms (MPNs) are increasingly being identified in women of childbearing potential. Pregnancy in women with MPNs is associated with maternal thrombosis, hemorrhage, and placental dysfunction leading to fetal growth restriction or loss.

Objective

To evaluate the association between the use of aspirin, heparin, interferon, or combinations and live birth rate and adverse maternal outcomes in pregnant women with MPNs.

Data Sources

Systematic searches of MEDLINE, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and the MEDLINE Epub Ahead of Print and In-Process and Other Non-Indexed Citations from inception to July 19, 2018, with no language restrictions, was conducted. Key search terms included myeloproliferative disorders, polycythemia vera, essential thrombocythemia, and primary myelofibrosis.

Study Selection

A study was eligible if it included pregnant patients with MPNs; interventions included aspirin, heparin, and/or interferon; there was a comparison group in which patients did not receive the intervention; the study reported on at least 1 of the study outcomes; and it was a randomized, case-control, or cohort study or series of at least 10 pregnancies. Data were extracted in duplicate; 0.5% of identified studies met selection criteria.

Data Extraction and Synthesis

The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and reported in accordance with Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Data were pooled using the Mantel-Haenszel approach.

Main Outcomes and Measures

Outcomes were the number of live births and maternal complications, specifically, arterial or venous thrombosis, hemorrhage, and preeclampsia.

Results

Twenty-two studies reporting on 1210 pregnancies were included. The live birth rate was 71.3% (95% CI, 65.1%-77.6%). Use of aspirin (11 studies, 227 patients; unadjusted odds ratio, 8.6; 95% CI, 4.0-18.1) and interferon (6 studies, 90 patients; unadjusted odds ratio, 9.7; 95% CI, 2.3-41.0) were associated with higher odds of live birth. Addition of heparin to aspirin was not associated with higher odds of live birth (6 studies, 96 patients; unadjusted odds ratio, 2.1; 95% CI, 0.5-9.0). The most common adverse maternal event was preeclampsia, with an incidence of 3.1% (95% CI, 1.7%-4.5%).

Conclusions and Relevance

Most studies reported on pregnancy with essential thrombocythemia. Few studies reported on pregnancy with polycythemia vera and none with myelofibrosis met the inclusion criteria. Most studies were retrospective and early pregnancy losses may have been underreported. Moderate-quality evidence suggests that aspirin or interferon is associated with higher odds of live birth in pregnant women with MPN.

Addressing and proposing solutions for unmet clinical needs in the management of myeloproliferative neoplasm-associated thrombosis: A consensus-based position paper

This article presents the results of a group discussion among an ad hoc constituted Panel of experts aimed at highlighting unmet clinical needs (UCNs) in the management of thrombotic risk and thrombotic events associated with Philadelphia-negative myeloproliferative neoplasms (Ph-neg MPNs). With the Delphi technique, the challenges in Ph-neg MPN-associated thrombosis were selected. The most clinically relevant UCNs resulted in: (1) providing evidence of the benefits and risks of direct oral anticoagulants, (2) providing evidence of the benefits and risks of cytoreduction in patients with splanchnic vein thrombosis without hypercythemia, (3) improving knowledge of the role of the mutated endothelium in the pathogenesis of thrombosis, (4) improving aspirin dosing regimens in essential thrombocythemia, (5) improving antithrombotic management of Ph-neg MPN-associated pregnancy, (6) providing evidence for the optimal duration of anticoagulation for prophylaxis of recurrent VTE, (7) improving knowledge of the association between somatic gene mutations and risk factors for thrombosis, and (8) improving the grading system of thrombosis risk in polycythemia vera. For each of these issues, proposals for advancement in research and clinical practice were addressed. Hopefully, this comprehensive overview will serve to inform the design and implementation of new studies in the field.

Developments in diagnosis and treatment of essential thrombocythemia

INTRODUCTION

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by thrombocytosis, increased risk of thrombotic/hemorrhagic events and clonal evolution into blast phase or myelofibrosis. Areas covered: The authors will discuss biology, diagnosis, prognosis, therapy, and outcome of ET. An accurate molecular-morphologic assessment is necessary in order to properly establish diagnosis and prognosis of ET. Stratification for thrombosis prediction is essential, and IPSET-t model is widely applied. The current treatment strategy is directed to lower the rate of vascular events using cytoreduction in patients at high risk. Prophylactic low dose aspirin indication is more uncertain. To date, therapies for patients who are resistant or intolerant to first-line treatments are scarce. Overall, life expectancy indicates an indolent disease, but IPSET model helps in predicting survival at the time of diagnosis. Expert opinion: Challenging for the future will be to share criteria for ET diagnosis with the community. New insights into the molecular pathogenesis of the disease will improve the prediction of clonal evolution and outcome, and lead to the use of disease-modifying treatments.

Characteristics and outcomes of patients with essential thrombocythemia or polycythemia vera diagnosed before 20 years of age: a systematic review

Although it is well known that myeloproliferative neoplasms occur in younger patients, few large cohorts of such patients have been reported. Thus, our knowledge about circumstances of diagnosis, outcome and treatment is limited, especially for children and young adults. We therefore performed a systematic review of cases, published since 2005, concerning patients aged below 20 years at the time of diagnosis of essential thrombocythemia or polycythemia vera. We identified 396 cases of essential thrombocythemia and 75 of polycythemia vera. The median age at diagnosis was 9.3 and 12 years, respectively, and females constituted 57.6% and 45% of the groups, respectively. Half of the patients were asymptomatic at diagnosis. The proportion of so-called triple negativity was high: 57% in essential thrombocythemia and 73% in polycythemia vera. The incidence of thrombosis during the follow-up was 9.3% in patients with polycythemia vera and less, 3.8%, in those with essential thrombocythemia. Venous events were predominant (84.2%), with hemorrhagic episodes being rarer (<5%). The risk of evolution also seemed low (2% to myelofibrosis and no reports of acute leukemia), but the median follow-up was only 50 months. Survival curves were not available. Half of the patients received an antithrombotic drug and 40.5% received a cytoreductive drug. All data should be analyzed with care because of the proportion of missing data (10.7% to 74.7%). This review highlights interesting points concerning this population of young patients with myeloproliferative neoplasms, including that such patients were identified as negative for all common driver mutations, but also shows the need for larger contemporary cohorts with longer follow-up to assess the true prognosis of these patients.

Multiple Placental Infarcts in a Pregnant Woman with Essential Thrombocythemia

Myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia (ET), and primary myelofibrosis, mainly occur in older patients, but have also been reported in younger patients. A "second peak" occurs in female patients in their thirties, particularly in ET; thus, the management of pregnancy is often discussed. We herein present the case of a 33-year-old woman with a high platelet count and multiple placental infarcts during delivery who was subsequently diagnosed with ET. Although there are no worldwide guidelines for the management of MPNs in pregnancy, the risk of thrombosis is markedly increased in these patients, and antithrombotic therapy should be considered.