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

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.

Acute invasive fungal sinusitis with orbital tip syndrome in patients on long-term use of ruxolitinib: a case report

INTRODUCTION

A long-term ruxolitinib-treated patient with primary myelofibrosis, who was co-infected with aspergillosis infection during a short period, developed acute invasive fungal sinusitis with consequent orbit apex syndrome. This may be the first reported case in the world. This is a 75-year-old Chinese man; the patient was admitted with 2-month history of headache accompanied by numbness and 8-day history of vision loss. The preliminary clinical diagnoses were suspected acute invasive fungal sinusitis or adenoid cystic carcinoma. We performed endoscopic debridement and antifungal therapy. About 90 days after surgery, magnetic resonance imaging revealed no recurrence of pathological tissue.

CONCLUSION

One of the bases for the occurrence of invasive fungal sinusitis may be the patient's long-term use of ruxolitinib for essential thrombocythemia. Some patients with invasive fungal sinuses have atypical nasal symptoms and are referred to the corresponding departments with eye and headache as the first symptoms. It is suggested that enhanced magnetic resonance imaging should be performed at an early stage. Surgical treatment in combination with antifungal and enhanced immunotherapy can effectively prevent the spread of infection and reduce the risk of death.

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.

Methods for Estimating Personal Disease Risk and Phylogenetic Diversity of Hematopoietic Stem Cells

An individual's chronological age does not always correspond to the health of different tissues in their body, especially in cases of disease. Therefore, estimating and contrasting the physiological age of tissues with an individual's chronological age may be a useful tool to diagnose disease and its progression. In this study, we present novel metrics to quantify the loss of phylogenetic diversity in hematopoietic stem cells (HSCs), which are precursors to most blood cell types and are associated with many blood-related diseases. These metrics showed an excellent correspondence with an age-related increase in blood cancer incidence, enabling a model to estimate the phylogeny-derived age (phyloAge) of HSCs present in an individual. The HSC phyloAge was generally older than the chronological age of patients suffering from myeloproliferative neoplasms (MPNs). We present a model that relates excess HSC aging with increased MPN risk. It predicted an over 200 times greater risk based on the HSC phylogenies of the youngest MPN patients analyzed. Our new metrics are designed to be robust to sampling biases and do not rely on prior knowledge of driver mutations or physiological assessments. Consequently, they complement conventional biomarker-based methods to estimate physiological age and disease risk.

Chorea and Cognitive Impairment in JAK2V617F-Positive Myeloproliferative Disorders: A Case Report and Literature Review

Chorea is a hyperkinetic movement disorder, accompanied by dystonia, myoclonus, tics, stereotypies, and tremors. It is characterized by excessive, purposeless movements that are distressing, irregularly timed, and randomly distributed. Chorea can be present in many diseases, such as hereditary, metabolic disturbance, drug-induced, and functional disorders, and, rarely, genetic, autoimmune, and infectious diseases. Primary myelofibrosis (PMF) is a myeloproliferative neoplasm that leads to ineffective clonal hematopoiesis, fibrous tissue deposits in the bone marrow, extramedullary hematopoiesis, and splenomegaly. In rare cases, following uncertain pathological mechanisms, it can present with chorea, particularly affecting the limbs, head, and orofaciolingual muscles. We present a case of a male patient with evolving PMF over several years who was admitted for progressive cognitive impairment and generalized involuntary movement disorder. We also present a review of all cases of myeloproliferative disorders presenting with chorea published in the last 40 years.

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.

Epidemiological Trends of Haematological Malignancies in Belgium 2004-2018: Older Patients Show the Greatest Improvement in Survival

(1) Background: Haematological malignancies (HMs) represent a heterogeneous group of mostly rare cancers that differ in pathophysiology, incidence, and outcome. (2) Methods: Our study aims to understand the epidemiological situation and trends of 24 main types of HMs in Belgium over a 15-year period, with a focus on the impact of age. Age-standardised incidence, average annual percentage change (AAPC), 5- and 10-year relative survival (RS) and RS trends were estimated for all HMs (N = 94,415) diagnosed between 2004 and 2018. (3) Results: Incidence rates of HM increased, mainly in the 70+ age group (AAPC: 3%). RS varied by age and HM type. For each HM type, outcome decreased with age. The greatest decrease with age in 5-year RS is observed for aggressive HM, acute myeloid leukaemia (AML), acute lymphoblastic leukaemia, and Burkitt lymphoma, from 67%, 90%, and 97% below 20 years, to 2%, 12%, and 16% above 80 years of age, respectively. The moderate improvement in 5-year RS over the 2004-2018 period for all HMs, of +5 percentage point (pp), masks highly heterogenous outcomes by HM type and age group. The most impressive improvements are observed in the 80+ group: +45, +33, +28, and +16 pp for Hodgkin lymphoma, immunoproliferative disorders, follicular lymphoma, and chronic myeloid leukaemia, respectively. (4) Conclusions: The increasing incidence and survival over the 2004-2018 period are likely explained by diagnostic and therapeutic innovations, which have spread to populations not targeted by clinical trials, especially older adults. This real-world population-based study highlights entities that need significant improvement, such as AML.

Multiparameter prediction of myeloid neoplasia risk

The myeloid neoplasms encompass acute myeloid leukemia, myelodysplastic syndromes and myeloproliferative neoplasms. Most cases arise from the shared ancestor of clonal hematopoiesis (CH). Here we analyze data from 454,340 UK Biobank participants, of whom 1,808 developed a myeloid neoplasm 0-15 years after recruitment. We describe the differences in CH mutational landscapes and hematology/biochemistry test parameters among individuals that later develop myeloid neoplasms (pre-MN) versus controls, finding that disease-specific changes are detectable years before diagnosis. By analyzing differences between 'pre-MN' and controls, we develop and validate Cox regression models quantifying the risk of progression to each myeloid neoplasm subtype. We construct 'MN-predict', a web application that generates time-dependent predictions with the input of basic blood tests and genetic data. Our study demonstrates that many individuals that develop myeloid neoplasms can be identified years in advance and provides a framework for disease-specific prognostication that will be of substantial use to researchers and physicians.

Polycythemia vera: 2024 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Polycythemia vera (PV) is a JAK2-mutated myeloproliferative neoplasm characterized by clonal erythrocytosis; other features include leukocytosis, thrombocytosis, splenomegaly, pruritus, constitutional symptoms, microcirculatory disturbances, and increased risk of thrombosis and progression into myelofibrosis (post-PV MF) or acute myeloid leukemia (AML).

DIAGNOSIS

A working diagnosis is considered in the presence of a JAK2 mutation associated with hemoglobin/hematocrit levels of >16.5 g/dL/49% in men or 16 g/dL/48% in women; morphologic confirmation by bone marrow examination is advised but not mandated.

CYTOGENETICS

Abnormal karyotype is seen in 15%-20% of patients with the most frequent sole abnormalities being +9 (5%), loss of chromosome Y (4%), +8 (3%), and 20q- (3%).

MUTATIONS

Over 50% of patients harbor DNA sequence variants/mutations other than JAK2, with the most frequent being TET2 (18%) and ASXL1 (15%). Prognostically adverse mutations include SRSF2, IDH2, RUNX1, and U2AF1, with a combined incidence of 5%-10%.

SURVIVAL AND PROGNOSIS

Median survival is ⁓15 years but exceeds 35 years for patients aged ≤40 years. Risk factors for survival include older age, leukocytosis, abnormal karyotype, and the presence of adverse mutations. Twenty-year risk for thrombosis, post-PV MF, or AML are ⁓26%, 16% and 4%, respectively.

RISK FACTORS FOR THROMBOSIS

Two risk categories are considered: high (age >60 years or thrombosis history) and low (absence of both risk factors). Additional predictors for arterial thrombosis include cardiovascular risk factors and for venous thrombosis higher absolute neutrophil count and JAK2V617F allele burden.

TREATMENT

Current goal of therapy is to prevent thrombosis. Periodic phlebotomy, with a hematocrit target of <45%, combined with once- or twice-daily aspirin (81 mg) therapy, absent contraindications, is the backbone of treatment in all patients, regardless of risk category. Cytoreductive therapy is reserved for high-risk disease with first-line drugs of choice being hydroxyurea and pegylated interferon-α and second-line busulfan and ruxolitinib. In addition, systemic anticoagulation is advised in patients with venous thrombosis history.

ADDITIONAL TREATMENT CONSIDERATIONS

At the present time, we do not consider a drug-induced reduction in JAK2V617F allele burden, which is often incomplete and seen not only with peg-IFN but also with ruxolitinib and busulfan, as an indicator of disease-modifying activity, unless accompanied by cytogenetic and independently-verified morphologic remission. Accordingly, we do not use the specific parameter to influence treatment choices. The current review also includes specific treatment strategies in the context of pregnancy, splanchnic vein thrombosis, pruritus, perioperative care, and post-PV MF.

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.

Healthcare resource utilization in patients with myeloproliferative neoplasms: A Danish nationwide matched cohort study

Few studies have assessed healthcare resource utilization (HRU) in patients with Philadelphia-negative myeloproliferative neoplasms (MPN) using a matched cohort design. Further, no detailed assessment of HRU in the years preceding an MPN diagnosis exists. We conducted a registry-based nationwide Danish cohort study, including patients with essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN diagnosed between January 2010 and December 2016. HRU data were summarized annually from 2 years before MPN diagnosis until emigration, death, or end of study (December 2017). We included 3342 MPN patients and 32 737 comparisons without an MPN diagnosis, matched on sex, age, region of residence, and level of education. During the study period, the difference in HRU (rate ratio) between patients and matched comparisons ranged from 1.0 to 1.5 for general practitioner contacts, 0.9 to 2.2 for hospitalizations, 0.9 to 3.8 for inpatient days, 1.0 to 4.0 for outpatient visits, 1.3 to 2.1 for emergency department visits, and 1.0 to 4.1 for treatments/examinations. In conclusion, MPN patients had overall higher HRU than the matched comparisons throughout the follow-up period (maximum 8 years). Further, MPN patients had substantially increased HRU in both the primary and secondary healthcare sector in the 2 years preceding the diagnosis.

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.

Impact of molecular profiling on the management of patients with myelofibrosis

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm (MPN) characterized by a highly heterogeneous clinical course, which can be complicated by severe constitutional symptoms, massive splenomegaly, progressive bone marrow failure, cardiovascular events, and development of acute leukemia. Constitutive signaling through the JAK-STAT pathway plays a fundamental role in its pathogenesis, generally due to activating mutations of JAK2, CALR and MPL genes (i.e., the MPN driver mutations), present in most MF patients. Next Generation Sequencing (NGS) panel testing has shown that additional somatic mutations can already be detected at the time of diagnosis in more than half of patients, and that they accumulate along the disease course. These mutations, mostly affecting epigenetic modifiers or spliceosome components, may cooperate with MPN drivers to favor clonal dominance or influence the clinical phenotype, and some, such as high molecular risk mutations, correlate with a more aggressive clinical course with poor treatment response. The current main role of molecular profiling in clinical practice is prognostication, principally for selecting high-risk patients who may be candidates for transplantation, the only curative treatment for MF to date. To this end, contemporary prognostic models incorporating molecular data are useful tools to discriminate different risk categories. Aside from certain clinical situations, decisions regarding medical treatment are not based on patient molecular profiling, yet this approach may become more relevant in novel treatment strategies, such as the use of vaccines against the mutant forms of JAK2 or CALR, or drugs directed against actionable molecular targets.

Changes in the incidence and overall survival of patients with myeloproliferative neoplasms between 2002 and 2016 in the United States

This analysis examined trends in incidence and survival among US adults with myeloproliferative neoplasms, including essential thrombocythemia (ET; n = 14,676), polycythemia vera (PV; n = 15,141), and primary myelofibrosis (PMF; n = 4214), using Surveillance, Epidemiology, and End User Results (SEER) data (SEER 18; 2002-2016). Incidence and survival rates over the study period and by diagnosis year (per 5-year time frames: 2002-2006; 2007-2011; 2012-2016) were assessed. The overall incidence rates (95% CI) were 1.55 (1.52-1.57) for ET, 1.57 (1.55-1.60) for PV, and 0.44 (0.43-0.45) per 100,000 person-years for PMF, with rising ET incidence. Five-year mortality over the study period was 19.2%, 19.0%, and 51.0% for ET, PV, and PMF, respectively. Improved survival over time was observed for PV and PMF, but not for ET. These findings highlight the need for effective ET therapies, as ET incidence has risen without concurrent improvements in survival over the past 2 decades.

Daily living and rehabilitation needs in patients and caregivers affected by myeloproliferative neoplasms (MPN): A qualitative study

AIMS AND OBJECTIVES

To explore experiences of daily living and identify rehabilitation needs in patients and caregivers living with myeloproliferative neoplasms.

BACKGROUND

Myeloproliferative neoplasms are chronic haematological cancers. Studies report a high symptom burden but little is known about supportive care and rehabilitation for this patient group.

DESIGN

Qualitative study with a phenomenological approach using focus group interviews to gather knowledge about the participants' lived experiences.

METHODS

Forty-eight patients and seven caregivers attending a 5-day rehabilitation course were interviewed in 12 focus groups. Systematic Text Condensation was used to analyse the interviews. Reporting adhered to COREQ.

RESULTS

Two main themes for patients were found: The loss of choice and identity due to the need to prioritise energy and The schism of being a person but also a patient. Patients described how living with myeloproliferative neoplasms meant having to prioritise energy and, therefore, losing freedom to choose activities. This changed their identity and impaired their quality of life. Patients of working age seemed to struggle the most in balancing the disease, family, social relationships and work. One main theme was found for caregivers: Influence of the disease. Caregivers reported how the disease limited their social lives, that the disease brought psychological strain, extra work, and that communication between couples was impaired. When both patients and caregivers participated in rehabilitation courses, they reported better understanding between couples and more open conversations. Rehabilitation needs identified were mainly in relation to psychosocial support and patient education, although needs varied across patients and caregivers.

CONCLUSIONS

Patients and caregivers expressed difficulties in adjusting to the lives the disease enforced upon them. Our findings indicate that myeloproliferative neoplasms patients and their caregivers would benefit from a combined model of psychosocial support, patient education, peer support and rehabilitation interventions based on an individual needs assessment.

RELEVANCE TO CLINICAL PRACTICE

Nurses can be responsible for individual needs assessments and refer patients and caregivers to suitable supportive care and rehabilitation interventions.

TRIAL REGISTRATION DETAILS

The study was approved by the Danish Data Protection agency (J.nr. 2008-58-0035).

The value of bone marrow, liver, and spleen imaging in diagnosis, prognostication, and follow-up monitoring of myeloproliferative neoplasms: a systematic review

Background

Diagnostic and treatment response criteria for the JAK2/CALR/MPL mutation-related myeloproliferative neoplasms (MPNs) are largely based on bone marrow (BM) biopsy results. However, these biopsies have several limitations, such as the risk of sampling error. Also, the prognostic impact of BM abnormalities is largely unclear. Although not currently used in clinical practice, imaging techniques might offer additional information. In this review, we investigated the value of BM, liver, and spleen imaging for diagnosis, prognostication, and response monitoring of the JAK2/CALR/MPL mutation-related MPNs (i.e. essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)).

Methods

A systematic literature search was performed via PubMed, Embase and the Cochrane Library up to 2020 March 26th. Of 5505 identified records, 55 publications met the eligibility criteria (i.e. containing original data on the imaging appearance of BM, spleen, or liver in adult ET, PV, or MF patients, published in a peer-reviewed journal, written in English).

Results

Many explorative studies described imaging features, sometimes with comparisons to clinical characteristics. Studies reporting measures of diagnostic accuracy included 1) splenic transient elastography to predict BM fibrosis grade in MF, 2) dynamic contrast-enhanced MRI to discern MF patients from ET patients and healthy controls, and 3) 18-fluorodeoxyglucose PET to detect residual disease after stem cell transplantation in MF. The diagnostic accuracies of radiography and ^99mTc-colloid scintigraphy were derived from several other articles. Except for the study on 18-fluorodeoxyglucose PET, we established substantial concerns regarding risk of bias and applicability across these studies, using the QUADAS-2 tool. Three publications described a correlation between imaging results and prognosis, of which one quantified the effect.

Conclusions

Based on current data, MRI (T1-weighted/STIR, Dixon) seems especially promising for the evaluation of BM fat content - and indirectly cellularity/fibrosis - in MF, and possibly for estimating BM cellularity in ET/PV. 18-fluorodeoxyglucose and 18-fluorothymidine PET/CT might be useful for evaluating BM fibrosis, with good reported accuracy of the former for the diagnosis of residual disease. Further research on these and other techniques is warranted to determine their exact value. Future researchers should improve methodology and focus on evaluation of diagnostic accuracy and prognostic implications of results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00405-7.

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.

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.

Targeting Abnormal Hematopoietic Stem Cells in Chronic Myeloid Leukemia and Philadelphia Chromosome-Negative Classical Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are unique hematopoietic stem cell disorders sharing mutations that constitutively activate the signal-transduction pathways involved in haematopoiesis. They are characterized by stem cell-derived clonal myeloproliferation. The key MPNs comprise chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). CML is defined by the presence of the Philadelphia (Ph) chromosome and BCR-ABL1 fusion gene. Despite effective cytoreductive agents and targeted therapy, complete CML/MPN stem cell eradication is rarely achieved. In this review article, we discuss the novel agents and combination therapy that can potentially abnormal hematopoietic stem cells in CML and MPNs and the CML/MPN stem cell-sustaining bone marrow microenvironment.

Aetiology of Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) have estimated annual incidence rates for polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis of 0.84, 1.03, and 0.47 per 100,000. Prevalence is much higher, particularly for PV and ET, as mortality rates are relatively low. Patients are often concerned about why they developed an MPN and epidemiological studies enable the identification of potential causative factors. Previous work in small heterogeneous studies has identified a variety of risk factors associated with MPNs including family history of MPN, autoimmune conditions, some occupational exposures, and blood donation. At a population level, germline predisposition factors in various populations have been associated with MPNs. The pilot MOSAICC (Myeloproliferative Neoplasm: An In-depth Case-Control) study is one of the largest epidemiological studies in MPN ever carried out to date. It demonstrated the most effective methods for carrying out a significant epidemiological study in this patient group including the best way of recruiting controls, as well as how to evaluate occupational and lifestyle exposures, evaluate symptoms, and collect biological samples. Significant results linked to MPNs in the pilot study of 106 patients included smoking, obesity, and childhood socioeconomic status. The methodology is now in place for a much larger ongoing MOSAICC study which should provide further insight into the potential causes of MPNs.

Risk of infections in patients with myeloproliferative neoplasms-a population-based cohort study of 8363 patients

Infections are a common complication in patients with many hematologic malignancies, however, whether patients with myeloproliferative neoplasms (MPN) also are at an increased risk of infections is largely unknown. To assess the risk of serious infections, we performed a large population-based matched cohort study in Sweden including 8 363 MPN patients and 32,405 controls using high-quality registers between the years 1992-2013 with follow-up until 2015. The hazard ratio (HR) of any infection was 2.0 (95% confidence interval 1.9-2.0), of bacterial infections 1.9 (1.8-2.0), and of viral infections 2.1 (1.9-2.3). One of the largest risk increases was that of sepsis, HR 2.6 (2.4-2.9). The HR of any infection was highest in primary myelofibrosis 3.7 (3.2-4.1), and significantly elevated in all MPN subtypes; 1.7 (1.6-1.8) in polycythemia vera and 1.7 (1.5-1.8) in essential thrombocythemia. There was no significant difference in risk of infections between untreated patients and patients treated with hydroxyurea or interferon-α during the years 2006-2013. These novel findings of an overall increased risk of infections in MPN patients, irrespective of common cytoreductive treatments, suggest the increased risk of infection is inherent to the MPN.