Chronic Leukemia: Clinical Aspects Basis of Medicine Unit 5 March 3, 2008

1. Chronic Leukemia: Clinical Aspects Basis of Medicine Unit 5March 3, 2008 Sarit Assouline, MD, MSc, FRCP(C) sarit.assouline@mcgill.ca

2. Basic Concepts Leukemia is a clonal disorder of bone marrow cells which results in the unrestrained growth of these cells. Leukemias which result from the clonal proliferation of lymphocytes and lymphocyte precursors are called lymphoid leukemias. The clonal proliferation of myeloid precursors gives rise to myeloid leukemias. Leukemias may be acute or chronic

3. Basic Concepts Based on these characteristics, leukemias are divided into four broad categories: Acute lymphoblastic leukemia (ALL) Acute myeloid leukemia (AML) Chronic lymphocytic leukemia (CLL) Chronic myeloid leukemia (CML)

4. Basic Concepts Acute vs. chronic leukemia Acute leukemia Rapid proliferation of abnormal clone that overtakes bone marrow and prevents normal hematopoiesis Severe anemia, thrombocytopenia, and neutropenia Patients are symptomatic at the outset Leukemic cells appear very immature (have open chromatin and nucleoli), and do not function normally

5. Basic concepts Chronic leukemia The malignant clone grows in such a way that, at least for most of the disease course, the growth of red cells, platelets and normal white blood cells is not significantly impaired. Patients often present because of an abnormal CBC and are asymptomatic Leukemic cells resemble mature, normal white cells and may even function normally

6. Chronic Leukemia Leukemias are divided into four broad categories: Acute lymphoblastic leukemia (ALL) Acute myeloid leukemia (AML) Chronic lymphocytic leukemia (CLL) Chronic myeloid leukemia (CML)

7. Chronic Myeloid Leukemia Definition: Clonal disorder of the pluripotent HSC Due to the translocation of the Abelson gene on chromosome 9 and bcr on chromosome 22 Results in unrestrained proliferation of HSC but with a preserved ability to differentiate So, there is an increased white cell count with many neutrophils and neutrophil precursors, and eosinophils, basophils, and monocytes

9. CML Pathobiology The BCR�ABL fusion protein, t(9;22), results in constitutive activation of ABL, a tyrosine kinase, in the cytoplasm ABL functions to: Induce cytokine independent growth in vitro Protect hematopoietic cells from apoptosis Protect cells from DNA damage

10. CML Pathobiology (cont�d) ABL functions to: Increase adhesion of hematopoietic cells to extracellular-matrix proteins Activate the same signaling cascades activated by cytokines that control the growth and differentiation of normal hematopoietic cells � SO CELLS DIFFERENTIATE

11. CML Pathobiology

12. Peripheral Blood

13. Chronic Myeloid Leukemia � Peripheral Blood

14. CML � Clinical Aspects Incidence is 1/100000 cases per year Median age is 53 years, but CML can occur at any age, including childhood Etiology unknown, ionizing radiation is a risk factor

15. CML-Clinical Aspects Clinical presentation: Most patients present in chronic phase 40% asymptomatic, abnormality detected on routine CBC Fatigue, anorexia, weight loss, night sweats Splenomegaly in 50% of cases Hepatomegaly may also occur

16. CML � Clinical Aspects Laboratory findings of chronic phase CML: CBC Hgb slightly low Platelets normal, elevated, reduced White blood cell count Elevated Left shifted: bands, myelocytes, metamyelocytes Increased basophils Increased eosinophils

17. CML � Clinical Aspects After a median of 3 � 5 years the disease can transform into an accelerated phase and/or blast crisis Accelerated phase: Results from new mutations in the HSC Presents with drop in platelet count, increase in basophil count, increase in blasts and promyelocytes Blast crisis/phase: Transformation to acute leukemia Mostly myeloid but may also be lymphoid

18. CML � Clinical Aspects Immunophenotyping: Not needed Cytogenetics: Philadelphia chromosome, t(9;22) Usually detected by cytogenetics or FISH, which can also quantitate the number of rearrangements in a sample of cells. PCR testing of peripheral-blood RNA is highly sensitive, and can detect 1 Ph-positive cell in 10-4 to 10-5 cells

19. Cytogenetics (karyotyping)

20. FISH cytogenetics

21. CML � Therapy Before 2001/Before imatinib mesylate (Gleevec) Interferon � only 10% of patients had a significant response Allogeneic stem cell transplant � only a small subset eligible, curative therapy Many given only hydroxyurea to control the white cell count but this did not alter disease course

22. CML � Treatment Imatinib mesylate Orally active, tyrosine kinase inhibitor Binds to the ATP binding site of ABL Inhibits autophosphorylation of ABL and function of ABL on downstream effectors

23. CML - Treatment

24. CML - Treatment Accelerated phase CML Responds to imatinib but at a lower rate Patients may return to chronic phase Blast phase or blast crisis CML Transiently responds to imatinib if at all Usually fatal within 6 months Can only be cured with allogeneic stem cell transplant

25. CML Clinical Case 52 yo man presents to peripheral hospital with left upper quadrant pain, weight loss and hematemesis He has been taking ibuprofen regularly for 8 weeks to treat his abdominal pain He has had melena for a few days On physical examination, he has massive splenomegaly reaching the iliac crest

26. CML Clinical Case A CBC is performed: Hgb 67 g/L, MCV 60 Platelets 579 x109/l WBC 159 x 109/l A differential shows elevated basophils (5%), eosinophils (3%), and a left shift in the neutrophil series with metamyelocytes, bands, and promyelocytes His LDH is elevated at 1500 mmol/L Uric acid is elevated

27. CML Clinical Case A gastroscopy is done: Diffuse gastritis, no ulcer, no tumour Serum ferritin is 4 with low serum iron, high TIBC, and low iron saturation

28. CML Clinical Case What has happened? Left upper quadrant pain is from splenomegaly Weight loss is from leukemic process and early satiety from splenomegaly Microcytic anemia is due to iron deficiency and acute blood loss Iron deficiency is from chronic and acute GI blood loss GI blood loss is from chronic NSAID use The high WBC is due likely to CML

29. CML Clinical case Management: The patient receives oral iron therapy (he is a Jehovah�s witness) NSAIDS are stopped, a proton pump inhibitor is given to reduce gastric acidity Hydroxyurea is given to reduce the white blood cell count while tests are done to confirm the diagnosis of CML Allopurinol is also given to reduce the risk of tumour lysis syndrome A bone marrow aspirate and biopsy are performed Cytogenetics and molecular tests are done

30. CML-Clinical Case Cytogenetics confirm the presence of the Philadelphia chromosome in 25/25 cells tested PCR testing is positive for bcr:abl and the level is determined compared to a housekeeping protein The patient is taken off hydroxyurea and started on imatinib mesylate

31. CML �Clinical Case After 4 weeks on imatinib The spleen is no longer palpable There is no more LUQ pain The CBC and differential are normal except for a slightly low hemoglobin with a normal MCV Iron therapy is stopped as iron indices have normalized Allopurinol is stopped

32. CML Clinical Case After 3 months on imatinib The CBC is normal except for a slight anemia A bone marrow aspirate is repeated It is morphologically normal 0/25 cells express the Philadelphia chromosome The patient has had a complete cytogenetic response PCR testing shows a 3 log reduction in bcr-abl transcript (major molecular response)

33. Chronic Lymphocytic Leukemia (CLL) Definition Leukemic transformation of the ANTIGEN EXPERIENCED* mature B cell (or T cell) progressive accumulation in the marrow and blood of long-lived mature leukemic lymphocytes due increased growth and reduced apoptosis

34. CLL - Morphology

36. Cellular Origin of B-CLL Mature B cell, antigen experienced with cell markers associated with activated B cells such as CD19, CD23, CD79b, dim IgM and IgGd Some CLL cells have an unmutated Vh gene and others have a mutated Vh gene This is similar to normal B cells that are exposed to antigen � some will have mutation of the Vh gene and others will not, based on the antigen to which they are exposed

37. Cellular Origin of CLL

38. Diagnostic criteria � NCI* >5 x 10-9/L lymphocytosis and cells morphologically mature in appearance 30% lymphocytes in a normocellular or hypercellular bone marrow A monoclonal B-cell phenotype with low levels of surface immunoglobulins and simultaneously showing CD5 positivity (dual positivity CD5, CD19-20 and CD23).

39. Clinical Features of CLL Epidemiology and natural history Most common form of leukemia in the Western world Disease of adulthood only, peak incidence is in the 6th decade, male:female 2:1 Overall median survival is 10-20 years untreated Some patients have a more aggressive disease, with median survival 2-3 years from diagnosis

40. Clinical Features of CLL Signs and symptoms May be asymptomatic but have elevated lymphocytes on a CBC Symptoms related to adenopathy, hepatosplenomegaly, B symptoms (fever, night sweats, weight loss) Anemia and thrombocytopenia usually mild Anemia and thrombocytopenia may be severe if there is AIHA, or ITP

41. Adenopathy

42. Splenomegaly

43. Splenomegaly

44. Clinical Features of CLL Immune phenomena Exaggerated response to mosquito bites Warm AIHA (autoimmune hemolytic anemia) ITP (Immune thrombocytopenic purpura) Hypogammaglobulinemia - increased risk of infections Richter�s transformation or syndrome 1-10% risk per year of transforming into an aggressive lymphoma (diffuse large B cell lymphoma)

45. Clinical Features of CLL Transformation to prolymphocytic leukemia More aggressive leukemia, difficult to treat Small lymphocytic lymphoma Nodular counterpart of CLL No lymphocytosis but adenopathy present Same disease, treated in the same way

46. Clinical Features of CLL Laboratory findings at diagnosis CBC normal except elevated lymphocyte may have mild anemia and thrombocytopenia at diagnosis smudge cells may be seen on blood smear

47. Clinical Features Laboratory Findings Biochemistry Usually normal, may have elevated LDH Immunoglobulin levels IgG, IgA, IgM � usually reduced as disease progresses Direct Coombs Present if there is autoimmune hemolytic anemia

48. Clinical Features of CLL Immunophenotyping CD19, CD20, CD5, dim IgM and IgD, kappa or lambda Cytogenetics Not used for diagnosis Predicts outcome (median survival) Deletions of 17p (p53 mutation) and 11q deletions associated with poor prognosis

49. Clinical Features of CLL Molecular diagnostics P53 mutations Vh gene mutations Occurs when the B cell receptor � immunoglobulin - first comes into contact with antigen Unmutated gene associated with a worse prognosis Mutations of V genes are detected by comparing DNA sequences of the genes in B cells with corresponding genes in the germ line. A sequence that differs from its germ-line counterpart by 2 percent or more is defined as mutated

50. Rai Staging System for CLL

51. Binet Staging System for CLL Binet Stage A: Fewer than 3 areas of lymphoid tissue are enlarged, with no anemia or thrombocytopenia. Binet Stage B: 3 or more areas of lymphoid tissue are enlarged, with no anemia or thrombocytopenia. Binet Stage C: Anemia and/or thrombocytopenia are present

52. Treatment of CLL There is no cure except with allogeneic stem cell transplant (bone marrow transplant) Most patients are not eligible for transplant because of age, comorbidities, absence of suitable donor Transplant is associated with high mortality rate

53. Treatment of CLL Indications for treatment Rai stage III or IV (anemia and thrombocytopenia) Bulky adenopathy or splenomegaly B symptoms (fever, night sweats, weight loss) Fatigue Rapid lymphocyte doubling time NOT DEGREE OF LYMPHOCYTOSIS

54. Treatment of CLL Treatment modalities Watchful waiting Chemotherapy: Fludarabine, chlorambucil, cyclophosphamide Immunotherapy: rituximab and alemtuzumab Allogeneic stem cell transplant Splenectomy Radiation therapy to bulky lymph nodes

55. Treatment of CLL Immune phenomena AIHA and ITP are treated as if they did not occur in the setting of CLL Steroids, splenectomy, etc. Hypogammaglobulinemia If there are recurrent infections, IVIG given (intravenous immunoglobulin)

56. Differential Diagnosis of CLL Any disorder that causes a lymphocytosis in the peripheral blood Prolymphocytic leukemia Hairy cell leukemia Non-Hodgkin lymphoma with circulating lymphoma cells Mononucleosis, and other viral infections with lymphocytosis ALL Usually distinguished by morphology, immunophenotyping or clinical course

57. Case Discussion - CLL 56 yo man presents after having felt some bumps under his arms P/E: small axillary and inguinal nodes felt CBC Hgb 140 (140-160) WBC 21 (4-11) Platelets 150 (150-440) Lymphocyte count 15 (1.0-4) Neutrophils 5 (2-7)

58. Further blood tests Smear:mature lymphocytosis, smudge cells Immunophenotyping shows CD5, CD19 coexpressing cells with dim surface IgM and sIgD, kappa restricted Cytogenetics by fish does not show deletion of 17p or 11q There is no p53 mutation on molecular testing Vh gene is unmutated

59. Case Discussion - CLL 6 months later patient presents with bruising CBC: Hgb 130, Platelets 5, WBC 22 (Ly 17) What has happened? ITP Treatment: Intravenous and oral steroids ITP resolves

60. Case Discussion - CLL 2 years later presents with enlarged lymph nodes and fatigue CBC: Hgb 88, Platelets 95, WBC 150, lymphocytes 145 Direct coombs negative Bone marrow aspirate and biopsy shows diffuse lymphocytosis, reduced eythropoiesis and myelopoiesis Decide to treat: Fludarabine, cyclophosphamide and rituxmab

61. Case Discussion - CLL Patient has good response to therapy with resolution of anemia (Hg 135), reduction in lymphocyte count (Ly 5), normalization of platelet count (plt-140) Lymph nodes return to normal size

62. Case Discussion - CLL 12 months later patient presents with bulky adenopathy especially in the right neck and complains of fever, night sweats, weight loss What has happened? Biopsy of neck shows diffuse large B cell lymphoma Richter�s transformation

63. Case Discussion - CLL Patient receives R-CHOP for lymphoma He has a complete response but 10 months later the lymphoma is back He is treated with chemotherapy but does not respond, he dies of pneumonia

64. Summary Chronic leukemia differs from acute leukemia in that: Leukemia cells are mature (CLL) or retain ability to mature (CML) Does not impair normal hematopoiesis (platelet count and Hgb may be normal or near normal at diagnosis) Leukemic cells may retain normal function (CML>CLL) Patients may be asymptomatic or mildly symptomatic at presentation

65. Summary CML Leukemia of pluripotent HSC due to t(9;22) Preservation of differentiation until evolution into blast crisis Chronic phase is most common phase of presentation Leukocytosis with left shift, elevated eosinophils and basophils, splenomegaly Usually treatable with imatinib

66. Summary CLL Leukemic transformation of ANTIGEN EXPERIENCED B cell with variation in mutation of Vh gene Mature lymphocytosis Disease of adulthood Variable clinical course Treated only for symptoms at this time Treatment includes numerous modalities

67. Acute Leukemia Review What is acute leukemia? A cancer of white cells A clonal proliferation of a mutated hematopoietic progenitor cell either committed to the myeloid or lymphoid lineage � AML or ALL

68. Review of Acute Leukemia How does acute leukemia affect normal hematopoiesis? Quickly overtakes the bone marrow and prevents normal hematopoiesis What are the clinical manifestations that result from this effect on the bone marrow? Short prodrome Anemia, thrombocytopenia, neutropenia Fatigue, dyspnea, bruising, bleeding and infection

69. Acute Leukemia Review What is the tumour lysis syndrome? It results from destruction of leukemic blasts either prior to or during therapy It causes the release of potassium, phosphate, and nucleotides It may cause arrhythmias due to hypocalcemia and hyperkalemia, and renal failure due to the release of nucleotides which are converted to uric acid and precipitation of calcium phosphate What is an Auer rod? Polymerization of granules, eosinophilic rod, seen in AML only

70. Acute Leukemia Review What is leukostasis? The plugging of small vessels by leukemic blasts This may cause intracranial hemorrhage, fluctuating level of consciousness, and an ARDS-like picture in the lungs What are the subtypes of ALL and how do you distinguish between them? Precursor B ALL and precursor T ALL Immunophenotyping for B cell markers and T cell markers

71. Review of Acute Leukemia What are the subtypes of AML according to the FAB classification? How are they distinguished? FAB: AML M0 to M7 Morphology and immunophenotyping What are the subtypes of AML according to the WHO classification? AML with recurrent genetic abnormalities AML with myelodysplasia AML therapy related AML not otherwise specified

72. Acute Leukemia Review Which tests are done to diagnose acute leukemia? Morphology on blood smear and bone marrow aspirate Cytochemical stains - allow to identify the type of leukemia morphologically Immunophenotyping � to distinguish ALL from AML, to define the type of AML by identifying cell surface markers Cytogenetics � to determine the mutation if one is present

73. Acute Leukemia Review What is the utility of cytogenetics? It defines certain leukemias Acute Promyelocytic Leukemia (AML M3) must have the t(15;17) (or variants thereof) It predicts outcome in AML and in ALL t(8;21), t(16;16), inv16, t(15;17) are good prognosis mutations in AML Hyperdiploidy, TEL/AML predict a good prognosis in ALL t(9;22) predicts a poor prognosis in ALL

74. Acute Leukemia Review What are the two main components of therapy of acute leukemia Supportive care Chemotherapy (do not memorize the drugs used) � induction, consolidation, maintenance What is a stem cell transplant Same thing as a bone marrow transplant It can be autologous It can be allogeneic

75. Acute Leukemia Review What distinguishes acute leukemia from chronic leukemia? In terms of leukemia cells: They are both clonal disorders They can both be either lymphoid or myeloid Acute leukemia cells, a.k.a. BLASTS, grow fast, are not functional, impair normal hematopoiesis Chronic leukemia cells, NOT known as blasts, do not grow as quickly, may retain normal function, do not impair normal hematopoiesis

76. Acute Leukemia Review What distinguishes acute leukemia from chronic leukemia? In terms of clinical presentation? Patients with acute leukemia are almost always symptomatic at presentation Patients with chronic leukemia often present because of an abnormal CBC and are often asymptomatic or mildy symptomatic

77. Acute Leukemia Review What distinguishes polycythemia vera from acute erythroblastic leukemia? Both are clonal disorders Both result in unrestrained growth of a single hematopoietic cell clone Both have something to do with red cell precursors In P.vera the precursor is a hematopoietic stem cell that produces an excess amount of red cells Acute erythroblastic leukemia phenotypically resembles an erythroid precursor but does not make red cells

78. Acute Leukemia Review Polycythemia vera vs. acute erythroblastic leukemia In polycythemia vera the clone has retained the ability to differentiate so that too many but still normal red cells are made, as are normal white cells and platelets In acute erythroblastic leukemia, the clone cannot differentiate and it overwhelms the bone marrow so that no red cells, platelets, or normal white cells can be produced

79. Acute Leukemia Review Is this review enough to be able to answer questions on the exam? No, read your notes. Is this review enough to be able to answer questions on the USMLE? Maybe�leukemia is not a priority of the USMLE�but you will have to know the clinical presentation