Myeloproliferative disorders

Introduction  Hemopoietic stem cell disorder Clonal Characterized by proliferation Granulocytic Erythroid Megakaryocytic  Interrelationship between Polycythaemia Essential thrombocythaemia myelofibrosis

Introduction / haemopoiesis

Introduction  Normal maturation (effective)  Increased number of  Red cells  Granulocytes  Platelets (Note: myeloproliferation in myelodysplastic syndrome is ineffective)  Frequent overlap of the clinical, laboratory & morphologic findings  Leucocytosis, thrombocytosis, increased megakaeryocytes, fibrosis & organomegaly blurs the boundaries  Hepatosplenomegaly  Sequestration of excess blood  Extramedullary haematopoiesis  Leukaemic infiltration

Rationale for classification  Classification is based on the lineage of the predominant proliferation  Level of marrow fibrosis  Clinical and laboratory data (FBP, BM, cytogenetic & molecular genetic)

Differential diagnosis Features distinguishing MPD from MDS, MDS/MPD & AML Disease cellularity BM % marrow blasts Maturation Morphology Haemato- poiesis Blood counts Large organs MPD Increase d Normal or < 10% PresentNormalEffectiv e One or more myeloid increase d Common MDS Usually increased Normal or < 20% PresentAbnorma l In- effective Low one or more cytopeni a Un- common MDS/ MPD Usually increased Normal or <20% PresentAbnorma l Effective or in- effective VariableCommon AML Usually increased Increase d >20% MinimalDysplasia can be present In- effective VariableUn- common

Clonal evolution Clonal evolution & stepwise progression to fibrosis, marrow failure or acute blast phase

Incidence and epidemiology  Disease of adult  Peak incidence in 7 th decade  6-9/100,000

Pathogenesis  Dysregulated proliferation  No specific genetic abnormality CML (Ph chromosome t(9;22) BCR/ABL)  Growth-factor independent proliferation PV, hypersensitiviy to IGF-1  Bone marrow fibrosis in all MPD Fibrosis is secondary phenomena  Fibroblasts are not from malignant clone  TGF-β & Platelet like growth factor

Prognosis  Depends on the proper diagnosis and early treatment Role of  IFN  BMT  Tyrosine kinase inhibitors

Myeloproliferative disorders  Clonal haematopoeitic disorders  Proliferation of one of myeloid lineages Granulocytic Erythroid Megakaryocytic  Relatively normal maturation

Myeloproliferative disorders WHO Classification of CMPD  Ch Myeloid leukemia  Ch Neutrophillic leukemia  Ch Eosinophillic leukemia / Hyper Eo Synd  Polycythemia Vera  Essential Thrombocythemia  Myelofibrosis  CMPD unclassifiable

Myeloproliferative disorders MPD PRV ET MF AML MDS RA RARS RAEB I RAEB II CMML CML

Myeloproliferative disorders  Ch Myeloid leukemia (BCR-ABL positive)  Polycythemia Vera  Essential Thrombocythemia  Myelofibrosis Specific clincopathologic criteria for diagnosis and distinct diseases, have common features Increased number of one or more myeloid cells Hepatosplenomegaly Hypercatabolism Clonal marrow hyperplasia without dysplasia Predisposition to evolve

Bone marrow stem cell Clonal abnormality Granulocyte precursors Red cell precursors MegakaryocytesReactive fibrosis Essential thrombocytosis (ET) Polycythaemia rubra vera (PRV) Myelofibrosis AML Chronic myeloid leukemia 70% 10% 30%

Epidemiology of CML  Median age range at presentation: 45 to 55 years  Incidence increases with age 12% - 30% of patients are >60 years old  At presentation 50% diagnosed by routine laboratory tests 85% diagnosed during chronic phase

Ionizing radiationLatent Period Atomic bomb survivors 11 years ( 2-25) Ankylosing spondylitis pts 3.6 years (1-6) No evidence of other genetic factors Chemical have not been associated with CML Incidence 1-1.5/100,000 population Male predominance Epidemiology of CML

Presentation Insidious onset Anorexia and weight loss Symptoms of anaemia Splenomegaly –may be massive Pt. maybe asymptomatic

The Philadelphia Chromosome XY19

The Philadelphia Chromosome: t(9;22) Translocation bcr-abl Fusion protein with tyrosine kinase activity 22 bcr abl Ph 9 9+ Philadelphia chromosome

Clinical Course: Phases of CML Chronic phase Median 4–6 years stabilization Accelerated phase Median duration up to 1 year Blastic phase (blast crisis) Median survival 3–6 months Terminal phase Advanced phases

Treatment of Chronic Myeloid leukemia ArsenicLissauer, 1865 RadiotherapyPusey, 1902 BusulfanGalton, 1953 HydroxyureaFishbein et al, 1964 AutograftingBuckner et al, 1974 Allogeneic BMT (SD)Doney et al, 1978 InterferonTalpaz et al, 1983 Allogeneic BMT (UD)Beatty et al, 1989 Donor Leukocytes Kolb et al, 1990 ImatinibDruker et al, 1998 Imatinib/Combination therapyO’Brien et al, 200……

CML Treatment Chemotherapy to reduce WCC - Hydroxyurea Interferon based treatment Allogeneic bone marrow transplant Molecular therapy - Imatinib

CML- CP survival post BMT (IBMTR ) Years Probability %

Issues related to BMT 70% long term cure rate Donor Availability Age of patient Length/stage of disease Treatment related mortality Long term sequalae – infertility, cGVHD

The Ideal Target for Molecular Therapy  Present in the majority of patients with a specific disease  Determined to be the causative abnormality  Has unique activity that is - Required for disease induction - Dispensable for normal cellular function

Mechanism of Action of Imatinib Goldman JM. Lancet. 2000;355: Bcr-Abl ATP Substrate Imatinib Y = Tyrosine P = Phosphate Bcr-Abl Substrate P P P P

Imatinib compared with interferon and low dose Cytarabine for newly diagnosed chronic-phase Chronic Myeloid leukemia S.G. O’Brien et al New England Journal of Medicine Vol. 348 March 2003

Imatinib vs Interferon in newly diagnosed CP Chronic Myeloid leukemia (18 months) CHR96%67% MCR83%20% CCR68% 7% Intolerance0.7%23% Progressive1.5% 7% disease Imatinib 400mg Interferon and Ara-C

Evolution of treatment goals HRMCRCCRPCR - HU IFN Imatinib BMT

Issues related to Imatinib Very few molecular responses (5-10%) Resistance in some patients Lack of response in some patients Expensive Long term toxicity/side effects unknown

CML Diagnosis Young with a well-matched donor Cosider for Allograft Allo SCT Start Imatinib at 400mg/day Poor response or Initial response Followed by Loss of response Add or substitute Other agents Allo-SCT Auto Good response maintained Continue Imatinib indefinitely

Polycythemia  True / Absolute Primary Polycythemia Secondary Polycythemia  Epo dependent Hypoxia dependent Hypoxia independent  Epo independent  Apparent / Relative Reduction in plasma volume

POLYCYTHEMIA VERA  Chronic, clonal myeloproliferative disorder characterized by an absolute increase in number of RBCs  2-3 /  Median age at presentation:  M/F: 0.8:1.2

POLYCYTHEMIA VERA JAK2 Mutation  JAK/STAT: cellular proliferation and cell survival  deficiency in mice at embryonic stage is lethal due to the absence of definitive erythropoiesis  Abnormal signaling in PV through JAK2 was first proposed in 2004  a single nucleotide JAK2 somatic mutation (JAK2V617F mutation) in the majority of PV patients

Polycythaemia vera (Polycythaemia rubra vera)  Definition of polycythemia  Raised packed cell volume (PCV / HCT)  Male > 0.51 (50%)  Female > 0.48 (48%)  Classification  Absolute  Primary proliferative polycythaemia (polycythaemia vera)  Secondary polycythaemia  Idiopathic erythrocytosis  Apparent  Plasma volume or red cell mass changes

Polycythaemia vera (Polycythaemia rubra vera)  Polycythaemia vera is a clonal stem cell disorder characterised by increased red cell production  Abnormal clones behave autonomous  Same abnormal stem cell give rise to granulocytes and platelets  Disease phase  Proliferative phase  “Spent” post-polycythaemic phase  Rarely transformed into acute leukemia

Polycythaemia vera (Polycythaemia rubra vera)  Clinical features  Age  years  May occur in young adults and rare in childhood  Majority patients present due to vascular complications  Thrombosis (including portal and splenic vein)  DVT  Hypertension  Headache, poor vision and dizziness  Skin complications (pruritus, erythromelalgia)  Haemorrhage (GIT) due to platelet defect

Polycythaemia vera (Polycythaemia rubra vera)  Hepatosplenomegaly  Erythromelalgia Increased skin temp Burning sensation Redness Liver 40% Spleen 70% Erythromelalgia

Polycythaemia vera (Polycythaemia rubra vera)  Laboratory features and morphology  Hb, PCV (HCT), and Red cell mass increased  Increased neutrophils and platelets  Normal NAP  Plasma urate high  Circulation erythroid precursors  Hypercellular bone marrow  Low serum erythropoietin Bone marrow in PV

Polycythaemia vera (Polycythaemia rubra vera)  Treatment  To decrease PVC (HCT) Venesection Chemotherapy  Treatment of complications

Clinical features  Plethora  Persistent leukocytosis  Persistent thrombocytosis  Microcytosis secondary to iron deficiency  Splenomegaly  Generalized pruritus (after bathing)  Unusual thrombosis (e.g., Budd-Chiari syndrome)  Erythromelalgia (acral dysesthesia and erythema)

Clinical features  Hypertention  Gout  Leukaemic transformation  Myelofibrosis

Diagnostic Criteria A1Raised red cell mass A2Normal O2 sats and EPO A3Palpable spleen A4No BCR-ABL fusion B1Thrombocytosis >400 x 109/L B2Neutrophilia >10 x 109/L B3Radiological splenomegaly B4Endogenous erythroid colonies A1+A2+either another A or two B establishes PV

Treatment  The mainstay of therapy in PV remains phlebotomy to keep the hematocrit below 45 percent in men and 42 percent in women  Additional hydroxyurea in high-risk pts for thrombosis (age over 70, prior thrombosis, platelet count >1,500,000/microL, presence of cardiovascular risk factors)  Aspirin ( mg/d) if no CI  IFNa (3mu three times per week) in patients with refractory pruritus, pregnancy  Anagrelide (0.5 mg qds/d) is used mainly to manage thrombocytosis in patients refractory to other treatments.  Allopurinol

Causes of secondary polycythemia  ERYTHROPOIETIN (EPO)-MEDIATED Hypoxia-Driven  Chronic lung disease  Right-to-left cardiopulmonary vascular shunts  High-altitude habitat  Chronic carbon monoxide exposure (e.g., smoking)  Hypoventilation syndromes including sleep apnea  Renal artery stenosis or an equivalent renal pathology Hypoxia-Independent (Pathologic EPO Production)  Malignant tumors Hepatocellular carcinoma Renal cell cancer Cerebellar hemangioblastoma  Nonmalignant conditions Uterine leiomyomas Renal cysts Postrenal transplantation Adrenal tumors

Causes of secondary polycythemia  EPO RECEPTOR–MEDIATED Activating mutation of the erythropoietin receptor  DRUG-ASSOCIATED EPO Doping Treatment with Androgen Preparations

Secondary polycythaemia  Polycythaemia due to known causes  Compensatory increased in EPO  High altitude  Hulmonary diseases  Heart dzs eg- cyanotic heart disease  Abnormal hemoglobin- High affinity Hb  Heavy cigarette smoker  Inappropriate EPO production  Renal disease-carcinoma, hydronephrosis  Tumors-fibromyoma and liver carcinoma

Secondary polycythaemia  Arterial blood gas  Hb electrophoresis  Oxygen dissociation curve  EPO level  Ultrasound abdomen  Chest X ray  Total red cell volume(51Cr)  Total plasma volume(125 I- albumin)

Relative polycythaemia  Apparent polycythaemia or pseudopolycythaemia due to plasma volume contraction  Causes Stress Cigarette smoker or alcohol intake Dehydration Plasma loss- burn injury

Differentiation of PV, Secondary PV and Relative Erythrocytosis

Essential Thrombocytosis  Clonal stem cell disorder characterized by marked thrombocytosis and abnormal platelet function  Plt count X 10 9 /L  Abnormal plt aggregation studies

Essential Thrombocythaemia (ET)  Clonal MPD  Persistent elevation of Plt>600 x109/l  Poorly understood  Lack of positive diagnostic criteria  2.5 cases/  M:F 2:1  Median age at diagnosis: 60, however 20% cases <40yrs

Clinical Features  Vasomotor Headache Lightheadedness Syncope Erythromelalgia (burning pain of the hands or feet associated with erythema and warmth) Transient visual disturbances (eg, amaurosis fujax, scintillating scotomata, ocular migraine)  Thrombosis and Haemorrhage  Transformation

Investigations ET is a diagnosis of exclusion  Rule out other causes of elevated platelet count

Diagnostic criteria for ET  Platelet count >600 x 109/L for at least 2 months  Megakaryocytic hyperplasia on bone marrow aspiration and biopsy  No cause for reactive thrombocytosis  Absence of the Philadelphia chromosome  Normal red blood cell (RBC) mass or a HCT <0.48  Presence of stainable iron in a bone marrow aspiration  No evidence of myelofibrosis  No evidence of MDS

Therapy of ET based on the risk of thrombosis

Essential thrombocythaemia Primary thrombocytosis / idiopathic thrombocytosis  Clonal myeloproliferative disease of megakaryocytic lineage  Sustained thrombocytosis  Increase megakaeryocytes  Thrombotic or/and haemorrhage episodes  Positive criteria  Platelet count >600 x 10 9 /L  Bone marrow biopsy; large and increased megas.

Essential thrombocythaemia Primary thrombocytosis / idiopathic thrombocytosis  Criteria of exclusion No evidence of Polycythaemia vera No evidence of CML No evidence of myelofibrosis (CIMF) No evidence of myelodysplastic syndrome No evidence of reactive thrombocytosis  Bleeding  Trauma  Post operation  Chronic iron def  Malignancy  Chronic infection  Connective tissue disorders  Post splenectomy

Essential thrombocythaemia Primary thrombocytosis / idiopathic thrombocytosis  Clinical features Haemorrhage Microvascular occlusion TIA, gangrene Splenic or hepatic vein thrombosis Hepatosplenomegaly

Essential thrombocythaemia Primary thrombocytosis / idiopathic thrombocytosis  Treatment  Anticoagulant  Chemotherapy  Role of aspirin  Disease course and prognosis  25 % develops myelofibrosis  Acute leukemia transformation  Death due to cardiovascular complication

Agnogenic Myeloid Metaplasia  Stem cell mutation causes hematopoietic abnormalities  Extramedullary hematopoiesis  BM fibrosis: uncontrolled production of fibroblasts from degenerating platelets result in dense thread-like scar tissue: dry BM tap  Differences from CML LAP inc., Ph neg, nRBC, splenomegaly, tear drop cell

Myelofibrosis

 Myeloproliferative disorder (monoclonal stem cell disorder) in which increased marrow fibrosis is dominant feature  Rare  yrs  Clinical: fatigue, weakness, malaise, fever/night sweats, abdominal pain, anorexia/wt loss, nasuea/vomiting  May be primary or secondary (breast cancer, prostate cancer, Hodgkin's disease, non-Hodgkin's lymphoma, autoimmune diseases)  Hematopoietic stem cells grow out of control, producing both immature blood cells and excess fibrous tissue—replacing normal marrow

Myelofibrosis  Extramedullary hematopoeisis—hepatic and splenic enlargement, thoracic paravertebral masses  Bones Uniform or heterogeneous increased density Spine (“sandwich sign” or diffuse density), pelvis, skull, ribs, proximal femur/humerus Cortical thickening in long bones Decreased T1 and T2 marrow signal  Bone marrow bx needed to confirm dz  Progressive bone marrow failure = severe anemia / thrombocytopenia/leukopenia risk of bleeding/infection  Slowly progressive dz leading to death  No available tx to effectively reverse progression; possible cure with bone marrow or stem cell transplantation (significant risks)

Myelofibrosis Chronic idiopathic myelofibrosis  Progressive fibrosis of the marrow & increase connective tissue element  Agnogenic myeloid metaplasia Extramedullary erythropoiesis Spleen Liver  Abnormal megakaryocytes Platelet derived growth factor (PDGF) Platelet factor 4 (PF-4)

Myelofibrosis Chronic idiopathic myelofibrosis  Insidious onset in older people  Splenomegaly- massive  Hypermetabolic symptoms Loss of weight, fever and night sweats Myelofibrosis Chronic idiopathic myelofibrosisc  Bleeding problems  Bone pain  Gout  Can transform to acute leukaemia in 10-20% of cases

Myelofibrosis Chronic idiopathic myelofibrosis  Anaemia  High WBC at presentation  Later leucopenia and thrombocytopenia  Leucoerythroblastic blood film  Tear drops red cells  Bone marrow aspiration- Failed due to fibrosis  Trephine biopsy- fibrotic hypercellular marrow  Increase in NAP score