Myelodysplastic syndromes, chronic myeloproliferative diseases, and myelodysplastic/myeloproliferative diseases

A systematic review and meta-analysis of the prevalence of thrombosis and bleeding at diagnosis of Philadelphia-negative myeloproliferative neoplasms

BACKGROUND

Philadelphia (Ph) chromosome-negative myeloproliferative neoplasms (MPNs) are a heterogeneous group of hematopoietic stem cell clonal diseases. Most patients with MPN are asymptomatic at diagnosis although some of them suffer from constitutional symptoms. Thrombosis and bleeding can also be one of the initial manifestations although the reported prevalence varied considerably across the studies. This systematic review and meta-analysis was conducted with the aims to better understand the prevalence and characteristics of thrombosis and bleeding among patients with newly-diagnosed MPN.

METHODS

Using a search strategy that included the terms for myeloproliferative neoplasms, thrombosis, and bleeding, two investigators independently searched for published articles indexed in the MEDLINE and EMBASE databases from inception to August 2018. The pooled prevalence was calculated using the DerSimonian-Laird random-effects model with a double arcsine transformation.

RESULTS

A total of 29 cohort studies (8 prospective and 21 retrospective) with 13,436 patients with MPN were included into this meta-analysis. At diagnosis, the pooled prevalence of overall thrombosis among patients with MPN was 20.0% (95% CI, 16.6-23.8%; I² 96%), with the pooled prevalence of arterial thrombosis of 16.2% (95% CI, 13.0-20.0%; I² 95%) and the pooled prevalence of venous thrombosis of 6.2% (95% CI, 4.9-7.8%; I² 89%). Common thrombotic events included cerebrovascular disease/transient ischemic attack, coronary heart disease, and deep venous thrombosis. The pooled prevalence of hemorrhagic complications among patients who were newly diagnosed with MPN patients was 6.2% (95% CI, 5.0-7.8%; I² 85%). Common sites of bleeding included gastrointestinal, mucosal, and cutaneous bleeding.

CONCLUSIONS

Thrombosis and bleeding are common initial manifestations of MPN. Investigations for MPN should be considered for patients who present with unexplained thrombosis or abnormal bleeding.

Myelodysplastic/myeloproliferative neoplasms

Myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) are rare de novo myeloid neoplasms that exhibit hybrid dysplastic and proliferative features at presentation. This SHP/EAHP Workshop session was uniquely problematic owing to the overlap between MDS/MPNs and both chronic myeloproliferative neoplasms and myelodysplasia. The borderline between MDS/MPNs and overt acute myeloid leukemias was also an issue, mainly related to the accurate and consistent delineation of blast equivalents such as promonocytes. Aside from juvenile myelomonocytic leukemia, genetic features defining specific MDS/MPN subtypes have not been identified. Consequently, there is little change in the 2008 World Health Organization classification of MDS/MPNs compared with the 2001 version.

Myelodysplastic syndromes: diagnosis and staging

Myelodysplastic syndromes (MDS) represent a heterogeneous group of hematologic disorders characterized by ineffective hematopoiesis and an increased risk of developing acute myelogenous leukemia (AML). Accurate diagnosis of MDS can be difficult, and its classification requires evaluation of cytopenias, bone marrow morphology, blast percentage, and cytogenetics. These factors, as well as patient performance status and red blood cell transfusion dependence, can be used to predict prognosis in MDS. Accurate diagnosis and classification are essential for subgroup identification and prognostic assessment of patients with MDS. This article reviews essential criteria for staging and subgroup classification and summarizes prognostic scoring systems that aid in risk stratification and selection of optimal therapy. Classification systems such as the World Health Organization (WHO) classification are widely used but do not always provide sufficient prognostic information. This limitation led to the creation of the International Prognostic Scoring System (IPSS). However, this system was designed to be used only at diagnosis and may not be suitable for serial assessment of patients whose disease can evolve over time. The WHO classification-based prognostic scoring system (WPSS) permits dynamic estimation of survival and risk of AML transformation at multiple time points during the natural course of MDS. Prognostic scoring systems such as WPSS allow for prediction of survival and risk of leukemic evolution at any time during the course of the disease. Such an approach may provide a useful adjunct for clinical decision making, including selection of appropriate treatment options.

Allogeneic bone marrow transplantation and donor lymphocyte infusion in a mouse model of irradiation-induced myelodysplastic/myeloproliferation syndrome (MD/MPS): evidence for a graft-versus-MD/MPS effect

The role of graft-versus-malignancy reactivity in the effects of allogeneic hematopoietic stem cell transplantation and donor lymphocyte infusion (DLI) for myelodysplastic syndromes is as yet not well established. Clinical data are limited and animal models are scarce. Here, we report on the effects of allogeneic bone marrow transplantation (alloBMT) and DLI in a novel model of irradiation-induced murine myelodysplastic/myeloproliferation syndrome (MD/MPS). Total body irradiation with 8.5 Gy in SJL/J mice gave rise to a lethal wasting syndrome in 60% of mice, characterized by 1 degrees normocellular bone marrow with dysplastic features in erythroid, myeloid and megakaryocytic cell lineages, 2 degrees lymphosplenomegaly with spleens harboring a prominent extramedullary hematopoiesis with erythroid, myeloid and megakaryocytic lineages exhibiting dysplastic features, and foci of dysplastic hematomyelopoiesis in the liver, 3 degrees peripheral thrombocytopenia and 4 degrees evidence of disseminated infection or leukemic transformation in selected animals. This clinicopathological picture was consistent with a murine form of MD/MPS. Syngeneic or allogeneic (BALB/c) T cell-depleted BMT could not prevent the occurrence of lethal MD/MPS. In contrast, DLI at weeks 2-4 after BMT led to restoration of the dysbalanced hematomyelopoiesis. However, severe DLI-induced acute graft-versus-host disease occurred, precluding a survival advantage. We present evidence of the existence of a post-alloBMT DLI-induced graft-versus-MD/MPS effect in murine irradiation-induced MD/MPS.

A critical reappraisal of the WHO classification of the chronic myeloproliferative disorders

Following the introduction of the WHO classification of chronic myeloproliferative disorders (MPDs), after approximately 5 years, a critical reappraisal appears to be warranted. Retrospective clinico-pathological evaluations conducted in the meantime, as well as the detection of new biomarkers, may aid in testing the validity of these new criteria. Based on a large series of patients with chronic myeloid leukemia (CML), an analysis of bone marrow (BM) features and risk classifications revealed that the fiber content exerted a most important and independent impact on prognosis. This finding was also supported in a prospective randomized study and therefore myelofibrosis should be included in any staging system in CML related to survival. Moreover, it is important to emphasize the dynamics of the disease process in MPDs, especially in polycythemia vera (PV) and chronic idiopathic myelofibrosis (CIMF). Latent-stage PV is difficult to recognize when adhering to the proposed limits for hemoglobin (or red cell mass) without regarding the erythropoietin (EPO) level, endogenous erythroid colonies (EECs) or BM histopathology. Initial PV may firstly present with complications and, when accompanied by a high platelet count, mimics essential thrombocythemia (ET). Consequently, BM morphology and EPO level should be entered as major diagnostic criteria for PV. To document more accurately the progress of disease, a simplified scoring system concerning myelofibrosis has to be included in the histological description of CIMF. The diagnostic guidelines of BM features in ET should be improved because, usually, there is neither a significant proliferation nor left-shifting of the granulo- and erythropoiesis detectable and no relevant increase in reticulin. A comparison of clinical data and BM morphology reveals that biomarkers (EPO, EECs, PRV-1, JAK2) show an overlapping pattern of positivity between the different subtypes of MPDs.

Grade of bone marrow fibrosis is associated with relevant hematological findings-a clinicopathological study on 865 patients with chronic idiopathic myelofibrosis

Controversy continues to exist regarding not only the exact definition and grading of myelofibrosis (MF), but also whether, and to what extent, this feature may be correlated with clinical findings. A retrospective study was performed involving 865 bone marrow (BM) biopsies together with the clinical records from patients with chronic idiopathic myelofibrosis (CIMF). Diagnosis was established according to the World Health Organization criteria, and assessment of MF followed a consensus scoring system that included four grades (MF-0 to MF-3). Histopathological and clinical evaluations were carried out in an independent fashion. Prefibrotic and early CIMF (MF-0/-1) were presented by 565 patients showing borderline to mild anemia and no or slight splenomegaly, but frequently, thrombocytosis exceeding 500x10(9)/l was shown. In 300 patients, manifest reticulin and collagen fibrosis (MF-2/-3) were characterized by marked anemia, gross splenomegaly, peripheral blasts, and normal to decreased platelet and leukocyte counts. The latter cohort was consistent with findings generally in keeping with MF with myeloid metaplasia. Regarding the stepwise evolution of disease, sequential BM examinations showed that in 103 patients, prefibrotic and early CIMF transformed into advanced stages accompanied by correspondingly developing clinical and histomorphological features. Survival analysis (univariate calculation) revealed a significantly more favorable prognosis in prefibrotic vs advanced stages of CIMF. On the other hand, higher classes of MF also exerted a higher clinical risk profile (Lille score). In conclusion, the dynamics of the disease process in CIMF are characterized by evolving MF in the BM and closely associated changes of relevant hematological findings.

The myelodysplastic syndromes: diagnosis and treatment

The myelodysplastic syndromes (MDSs) are common, acquired, clinically challenging hematologic conditions that are characterized by bone marrow failure and a risk of progression to acute leukemia. These disorders can arise de novo, especially in elderly patients or, less often, as a consequence of prior chemotherapy or radiotherapy for an unrelated disease. The MDS classification systems were revised recently and updated. These refined classification and prognostic schemes help stratify patients by their risk of leukemia progression and death; this knowledge can help clinicians select appropriate therapy. Although many treatments for MDS have been proposed and evaluated, at present, only hematopoietic stem cell transplantation offers any real hope for cure, and no available therapy beyond general supportive care offers benefit to more than a minority of patients. However, recent clinical trials enrolling patients with MDS have reported encouraging results with use of newer drugs, including lenalidomide, decitabine, and darbepoetin alfa. Other exciting treatment regimens are being tested. Here, we present a contemporary, practical clinical approach to the diagnosis and risk-stratified treatment of MDS. We review when to suspect MDS, detail how to evaluate patients who may have a form of the condition, explain key features of treatments that are currently available in the United States, and summarize a general, common-sense therapeutic approach to patients with MDS.

Bone Marrow Histopathology in Myeloproliferative Disorders—Current Diagnostic Approach

Current diagnostic issues in chronic myeloproliferative disorders (MPDs) include the differentiation of essential thrombocythemia (ET) from its mimics: early (prefibrotic) stages of chronic idiopathic myelofibrosis (CIMF) and early polycythemia vera (PV), both of which can be associated with thrombocytosis. Applying a systematic evaluation of bone marrow histopathology, in accordance with the current World Health Organization (WHO) classification system, it is possible to identify cases of true ET as opposed to false ET, usually early-stage CIMF accompanied by an excess of platelets. This distinction is important because the frequency of complications such as progression to overt myelofibrosis, blastic crisis, and overall prognosis are significantly different in the two conditions. The diagnostic criteria of the Polycythemia Vera Study Group (PVSG) do not adequately define the initial stages of PV, nor do they distinguish PV with thrombocytosis from ET. Differentiation of the two is possible by bone marrow histopathology, which also is highly predictive (96%) in distinguishing PV from secondary polycythemia. In conclusion, bone marrow biopsy is an important diagnostic tool for distinguishing specific subtypes of MPD and should be a mandatory step for entry evaluation and follow-up of patients enrolled in prospective studies and/or clinical trials.