Non-Leukemic Myeloproliferative Disorders PDF

NON - LEUKAEMIC MYELOPROLIFERATIVE DISORDERS DR OLATINWO A.T Outline Introduction – Definition – Classification – Risk factors Pathophysiology Polycythaemia Polycythaemia vera Essential thrombocythaemia Primary myelofibrosis Other myeloid neoplasms ass...

NON - LEUKAEMIC MYELOPROLIFERATIVE DISORDERS DR OLATINWO A.T Outline Introduction – Definition – Classification – Risk factors Pathophysiology Polycythaemia Polycythaemia vera Essential thrombocythaemia Primary myelofibrosis Other myeloid neoplasms associated with point mutations Introducti on Definition Myeloproliferative neoplasms (MPN) are a group of stem cell disorders: – Characterized by clonal proliferation – Involving one or more haemopoietic components – Lead to increase in one or more mature blood cells progeny – In the bone marrow and in many cases the liver and the spleen  Introduction contd Classification Chronic myelogenous leukaemia (BCR-ABL1 positive) Chronic neutrophilic leukaemia Polycythaemia (rubra) vera (PV) Essential thrombocythaemia (ET) Primary myelofibrosis (MF) Chronic eosinophilic leukaemia not otherwise specified Mastocytosis (MS) Myeloproliferative neoplasms, unclassifiable Myeloid and lymphoid neoplasms associated with eosinophilia and abnormalities of PDGFRA,PDGFRB or FGFR1  Introduction contd The MPN especially the non- leukaemic/ classical ones {Polycythaemia [rubra] vera (PV), Essential thrombocythaemia (ET) and Primary myelofibrosis (MF)} are closely related to each other – Clinically, morphologically and in molecular characteristics Transitional forms can occur Can evolve from one entity into another or to AML  Introduction contd Risk factors – Radiation – Industrial solvents Benzene, toluene  Pathophysiology MPN are associated with clonal abnormalities involving genes that code for receptor or cytoplasmic tyrosine kinase The most common one is cytoplasmic tyrosine kinase, Janus-associated kinase 2(JAK2 V617F). Present in 98%, 58% and 50% of PV, MF and ET respectively. JAK2 V617F has a negative regulatory effect, allowing the JAK 2 protein to become activated even when no growth factor is bound to it. This result in increased cell survival and proliferation Pathophysiology (role of JAK 2 mutation)  Genetic Mutations in MPNs  Polycythemia Definition: An ↑Hb concentration above the upper limit of normal for the age and sex of the patient Classification: – Absolute polycythaemia (erythrocytosis) Red cell mass (volume) is raised to > 125% of that expected for body mass and gender Normal red cell mass: male =25-35mL/kg, female = 22- 32mL/kg Total plasma volume is normal (40 -50mL/kg) Absolute polycythaemia is further divided into primary and secondary polycythaemia  Polycythaemia – Relative (pseudopolycythaemia) contd The red cell volume is normal Plasma volume is reduced Note: – If the PCV is > 0.60 (60%) then the red cell mass is certainly raised – Hb of > 18.5g/dL or PCV of >0.52(52%) in men, and Hb of > 16.5g/dL or PCV of >0.48(48%) in women indicate that erythrocytosis is likely but the plasma must be measured to confirm this  Polycythaemia Causes of contd polycythaemia – Primary erythrocytosis Congenital : erythropoietin receptor mutations Acquired : polythaemia vera – Secondary erythrocytosis Congenital – Defects of the oxygen- sensing pathway: VHL Polycythaemia contd Acquired – Erythropoietin-mediated : central hypoxia, chronic lung disease, right to left cardiopulmonary shunts, carbon monoxide poisoning, smoking, obstructive sleep apnoea, high altitude – Local hypoxia: renal artery stenosis, end-stage renal disease, hydronephrosis, renal cyst, post-renal transplant erythrocytosis – Pathologic erythropoietin production » Tumours: cerebellar haemangioblastoma, meningioma, parathyroid tumours, hepatocellular carcinoma, renal cell cancer, phaeochromocytoma, uterine leiomyoma » Drug-associated: erythropoietin administration, androgen administration  Polycythaemia contd Diagnosis: There is a three-stage approach to diagnosis of polycythaemia – Stage 1: History and examination FBC/Film JAK2 mutation Serum ferritin Renal and liver function tests If JAK2 is negative and there is no clear secondary cause, proceed to stage 2 Polycythaemia cont’ – Stage 2: Red cell mass Arterial oxygen saturation Abdominal ultrasound Serum erythropoietin level Bone marrow aspiration and trephine Cytogenetic analysis BFUE culture Specialized tests may then be required – Stage 3: Arterial oxygen dissociation Sleep study Lung function studies Gene mutations EPOR, VHL, PHD2 Polycythaemia vera (PV) It is and acquired erythrocytosis caused by mutations in the JAK2 gene There is a somatic mutation of a single stem cell giving its progeny a proliferative advantage The JAK 2 mutation is seen in 95-98% of cases Mutation in exon 12 is seen in < 5% There is polycythaemia, as well as granulocytosis and thrombocytosis in many patients Polycythaemia vera cont’ Clinical features: mainly due to erythrocytosis induced hyperviscosity or hypermetabolism. – Rare in children and young adults. Peak age incidence is varies from 50-60yrs – Headaches, dizziness, blurred vision, tinnitus, erythromyalgia, insomnia, amnesia, vertigo Polycythaemia vera cont’ – Thrombotic complications: Cerebrovascular accident, myocardial infarction, deep venous thrombosis, pulmonary embolism, peripheral arterial occlusion (gangrene). – Night sweats. Pruritus especially after hot bath – Plethoric appearance: ruddy cyanosis, conjunctival suffusion – Hepatosplenomegaly – Haemorrhage: GIT, uterine, cerebral, epistaxis, ecchymoses and gingival haemorrhage – Hypertention – Gout. Polycythaemia vera cont’ Laboratory features – Hb and PCV and red cell count are increased (≥60% in males or ≥56% in females) – Absolute increase in red cell mass (>36ml/kg in males and >32mls/kg in females) – Neutrophilia in > 50% of patients and basophilia in some – Thrombocytosis in about 50% of patients – JAK2 mutations in bone marrow and peripheral blood granulocytes in Polycythaemia vera – Bone marrow biopsy: trilineage hypercellularity (panmyelosis) – Serum erythropoietin is low – Serum uric acid is often raised. Serum LDH is normal – Raised Vit B12 level and unbound B12 binding capacity due to increased transcobalamin III produced by the granulocytes. – Increased presence of circulating erythroid progenitors (CFUE, BFUE) and grow in vitro independent of added erythropoietin – Chromosomal abnormalities: deletions 9p or 20q and TET-2 occur in 10-20% Polycythaemia vera Diagnosis: (WHO Criteria) – Major Criteria 1. Hb >18.5g/dL in males and >16.5g/dL in females OR Hb or PCV > 99th percentile of reference ag sex, range for altitude of residence e, or OR Hb >17.5g/dL in males, >15g/dL in females if associated with sustained increase of ≥2g/dL from baseline that cannot be attributed to correction of iron deficiency OR Red cell mass >25% above the normal predicted value 2. Presence of JAK 2 V617F or similar mutation such as JAK2 exon 12 mutation  Polycythaemia vera – Minor criteria 1. Bone marrow trephine with trilineage hyperplasia 2. Subnormal serum erythropoietin level 3. Endogenous erythroid colony (EEC) formation in vitro PV is confirmed in the presence of 2 major criteria and 1 minor criterion or first major criterion and 2 minor criteria Polycythaemia vera Treatment : the aim is to maintain a normal FBC (PCV at about 45% and PLT < 400 x109/L) Goals of treatment – Reduction of excess red cells and other cellular elements from circulation – To lower the blood viscosity thereby improving blood circulation and reducing thrombotic events. Polycythaemia vera Modalities: – Venesection (Phlebotomy): to reduce the PCV to ≤45%. 500ml of whole blood 2-3 x weekly Useful at start of therapy More beneficial in younger patients and in mild disease. Complicated by iron deficiency Does not control platelet and granulocyte count Polycythaemia vera – JAK2 inhibitors: Main stay of treatment. Ruxolitinib (INCB018424) 15mg po bid. Reduces the levels of pro-inflammatory cytokines TG101348 CYT387 also po and also inhibits JAK1. associated with amelioration of anaemia in MPN. Lestaurtinib (CEP-701) also inhibits FLT3 Polycythaemia vera cont’ – Myelosuppressive Therapy To induce myelosupression Indicated in poor tolerance of venesection, symptomatic splenomegaly, thrombocytosis, weight loss or night sweats Use may be associated with increased transformation to leukaemia especially with busulphan Drugs: – Daily hydroxyurea – chlorambucil – Busulphan intermitently and mostly in the older patients – cyclophosphamide Interferon. Often used in younger patients to avoid early exposure to chemotherapy. Polycythaemia vera – Radiotherapy using Phosphorus-32 Indicated only in older patients with severe disease. May cause secondary leukaemia and therefore no longer popular – Adjunct therapy Surgery: indicated in painful splenomegaly and/or recurrent thrombotic associated splenic infartion Low dose Aspirin to reduce thrombotic complications Polycythaemia vera Course and prognosis – Generally good. Median survival of 10- 16 years – Major clinical problems are thrombosis and haemorrhage – About 30% of patients transform to myelofibrosis and 5% to acute leukaemia Essential thrombocythaemia (ET) This is characterized by – Megakaryocyte proliferation resulting in – Sustained thrombocytosis of >450x 109/L – 50% of patients show the JAK2 mutation – About 4% show the MPL mutations – A rare primary familial form in children have been associated with mutations in the genes for thrombopoietin or its receptor MPL ET cont’ Clinical features: – About 50% are asymptomatic and diagnosis is coincidental – Found mainly between the ages of 50 and 70 with equal sex incidence – They present mainly with thrombosis (arterial/venous) or haemorrhage (due to abnormal platelet function) – Vaso-occlusive phenomena Erythromyalgia cynosis and necrosis of the toes and fingers may occur in severe cases Transient ischaemic attack (TIA) Dizziness, seizures, CVA, priapism Multiple placental infarctions and high risk of recurrent abortions, fetal growth retardation, premature deliveries and abruptio placentae – Mild to moderate splenomegaly – Some patients (JAK2 +ve) may present with Budd- Chiari syndrome ET cont’ Laboratory features: – Blood film: abnormal large platelets and megakaryocytes fragments may be seen – BM biopsy: hyperplastic, predominantly the megakaryocytic lineage with abnormal megakaryocytes – Cytogenetic and molecular analysis must be done to rule out BCR-ABL+ CML – Other causes of thrombocytosis must also be excluded ET cont’ ET cont’ Diagnosis: Certain diagnostic criteria have been suggested: A1=sustained platelet count of > 450 x 109/L A2 = presence of acquired pathogenetic mutation (in JAK2 or MPL) A4 A3==nonoother reactive cause myeloid for malignancy: PV, norm thrombocytosis andoriron myelofibrosis, CML MDS stores al A5= BM trephine histology showing increased megakaryocytes with dysplastic forms Diagnosis requires A1-A3 or A1 + A3-A5 ET cont’ Causes of reactive thrombocytosis – Iron deficiency – Blood loss (acute or chronic) – Hyposplenism/splenectomy – Surgery – Chronic inflammation: vasculitides, inflammatory bowel disease, connective tissue disease, rheumatoid arthritis, chronic infections – Malignancies – Rebound thrombocytosis: Post treatment for ITP or recovery from chemotherapy – Drugs : Vincristine ET Treatment : cont’ The aim is to reduce the risk of thrombosis or haemorrhage – Patients are classified into: – High- risk: > 60yrs of age, Previous thrombosis Thrombocytosis of >1500 x109/L. – Platelepheresis – Myelosuppressive agents: Hydroxyurea, chlrambucil, busulphan, cyclophosphomide – Anagrlide can be used as a second line drug. The two drug can be combined. ET cont’ – Medium –risk: 40-60years – Low-risk: 20cm) with associated symptoms – Hepatomegaly – Hypermetabolic symptoms: weight loss, fever, anorexia, night sweats – Haemorrhage – Bone pain – Gout PMF cont’ Laboratory features: – FBC: Anaemia is usual but Hb may be increased in some patients WBC and platelet counts are frequently high initially but at later stage leucopenia and thromcytopenia set in Leucoerythroblastic and tear drop poikilocytosis are seen in blood film – Bone marrow biopsy: Aspiration is usually unobtainable. Trephine biopsy shows a fibrotic hypercellulr marrow and varying reticulin and/or collagin deposits Increased megakaryocytes is frequent PMF cont’ – Splenic aspiration and/or liver biopsy show trilineage extramedullary haemopoiesis – Cytogenetic abnormalities is found in 60% : 13q and 20q deletions, trisomy 8 and abnormalities in chromosomes 1, 5, 7 and 9 – JAK2 mutation in about 50% – High serum urate and LDH levels – 10-20% may transform to AML PMF cont’ PMF cont, Diagnosis of PMF (WHO diagnostic criteria) – Major criteria 1. Megakaryocyte proliferation and atypia accompanied by either reticulin and/or fibrosis OR In the absence of reticulin fibrosis, the megakaryocyte changes must be accompanied by increased marrow cellularity, granulocytic proliferation and often increased erythropoiesis (pre-fibrotic PMF) 2.Not meeting WHO criteria for CML, PV, MDS or other myeloid neoplasms PMF cont, 3. Demonstration of JAK2V617F or other clonal marker such as MPLW515K/L OR No evidence of reactive marrow fibrosis – Minor criteria 1. Leucoerythroblastosis 2. Increased serum lactic dehydrogenase (LDH) 3. Anaemia 4. Palpable splenomegaly PMF is diagnosed in the presence of 3 major and 2 minor criteria. PMF cont’ Differencial daignosis of marrow fibrosis – Haematological malignancies: PMF, CML, AML (M7), MDS, myeloma, hairy-cell leukaemia, NHL, HD, systemic mastocytosis – Metastatic carcinoma – Infections: TB, Leishmaniasis – Drugs/toxins: Benzene, thorotrast, irradiation – Bone disease: Pagets disease, osteopetrosis, hyperparatyroidism, hypoparathyroidism – Inflammatory diseases: Systemic sclerosis, SLE – Other: Grey platelet syndrome PMF cont’ Treatment: Usually palliative and aimed at the effects of anaemia and splenomegaly – Blood transfusion and regular folic acid – Hydroxyurea for splenomegaly and hypermetabolic symptoms – Busulphan – Anagrelide to relieve thrombocytosis – JAK2 Inhibitors – Thalidomide, lenalidomide, azacytidine and histones deacetylase some of which are undergoing clinical trials – Danazole and androgen may improve anaemia. PMF cont’ – Erythropoietin – Splenectomy indicated in patients with severe symptomatic splenomegaly – Splenic radiation as an option to splenectomy – Allopurinol – Allogeneic stem cell transplantation PMF cont’ Course and prognosis – Median survival is < 5years – Bad prognosis when: Hb is < 10g/dL Leucopenia of < 4 x 109/L or >30 x 109/L Elevation in the circulating CD34+ cell count above 300 x 106/Land presence of abnormal chromosomes – About 10% transform to AML MPNs References – Postgraduate Haematology : A.V.Hoffbrand – Handbook of Haemato-oncology chemotherapy: M.A. Durosinmi – Nordic Guidlne on the Diagnosis and Treatment of Patients with MPN: Nordic MPN Study Group – Essential Haematology: A.V. Hoffbrand – NPMCN Update material on Myeloproliferative Neoplasms by Dr A.H  THANK YOU FOR LISTENING