Leukemia

Leukemia Microchapters
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Patient Information
Overview
Classification AML CML ALL CLL
Differentiating Leukemia from other Diseases
Epidemiology and Demographics
Prognosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2], Usama Talib, BSc, MD [3], Sadaf Sharfaei M.D.[4]

Synonyms and keywords: Leukaemia

Overview

Leukemia (Greek leukos, “white”; haima, “blood”) could be defined as a group of hematopoietic stem cell malignancies due to genetic abnormalities that may lead to clonal proliferation of these cells. These group of diseases are classified based on type of hematopoietic stem cell involvement and duration of disease. The leukemias are the most common malignancies among children younger than 15 years. Among them, ALL is the most common leukemia accounts for 77% of childhood leukemia. However, CLL is the most common form of leukemia in adults, it accounts for 30% of all leukemias in the United states. The increased rate of proliferation and decreased rate of apoptosis in this progeny of cells may compromise normal bone marrow function and ultimately marrow failure. Clinical manifestations, diagnosis, laboratory findings, and therapy are different according to the type of malignancy.

Classification

Leukemia may be classified as follows:

Leukemia

Lymphoid progeny

Myeloid progeny

Acute lymphoblastic leukemia (ALL)

Chronic lymphocytic leukemia (CLL)

Acute Myeloid Leukemia (AML)

Chronic myeloid leukemia (CML)

Differentiating Leukemia from other Diseases

Leukemia must be differentiated from various diseases that cause weight loss, night sweats, hepatosplenomegaly, and palpable lymph nodes, such as hairy cell leukaemia, prolymphocytic leukaemia, follicular lymphoma, and mantle cell lymphoma. Based on the expression of cell surface markers, the table below differentiates different types of leukemia from other diseases that cause similar clinical presentations:

Disease	Etiology	Clinical Manifestation											Laboratory Findings			Gold standard diagnosis	Associated findings
		Demography	History	Symptoms				Signs
				Constitutional symptoms	Weight	Bleeding	Abdominal Pain	Vital sign	Jaundice	LAP	Hepatosplenomegaly	Other	CBC	Histopathology	Other
Acute myelogenous leukemia	Clonal proliferation of malignant myeloid blast cells in the marrow Genetic abnormalities t(8;21), inv(16), and t(15;17)	The most common type of acute leukemia in adults Median age of 63 years old More in congenital disorders such as Down syndrome, Bloom syndrome	Smoking, previous chemotherapy or radiation therapy, myelodysplastic syndrome, and exposure to the chemical benzene	Fatigue	↓	+	–	Fever	–	Rare	Mild and asymptomatic	Bone tenderness Dyspnea Leukemia cutis Swelling of the gums Chloroma	Anemia Thrombocytopenia Leukocytosis or leukopenia	Leukemic blasts Positive Auer rods		Flow cytometry > 20% blasts of myeloid lineage	Persistent or frequent infections Fatal within weeks or months if left untreated
Acute lymphoblastic leukemia	Arrest of lymphoblasts Chromosomal translocations: t(9;22) , t(12;21), t(5;14), t(1;19)	The most common form of cancer in children Peak 2-5 years of age Boys > girls	History of cancer History of drug exposure	Generalized weakness and fatigue	↓	+	–	Fever	–	+	+	Musculoskeletal pain Dyspnea Pallor Papilledema Nuchal rigidity Cranial nerve palsy Testicular enlargement Mediastinal mass	Anemia Thrombocytopenia Normal or slightly increased WBC counts	Lymphoblasts Atypical cells		Bone marrow biopsy	CNS involvement
Chronic myelogenous leukemia	Dysregulated production and uncontrolled proliferation of mature and maturing granulocytes BCR-ABL1 fusion gene Autosomal dominant mutation	Median age 50 years old		Generalized weakness and fatigue Early satiety	↓	+	Abdominal fullness	Normal	–	–	+	Asymptomatic Blast crisis resembling acute leukemia Excessive sweating Papilledema Tenderness over the lower sternum	Anemia WBC > 100,000/microL Absolute basophilia and eosinophilia Plt > 600,000 to 700,000/microL	All cells of the neutrophilic series, from myeloblasts to mature neutrophils Myelocyte bulge	Low leukocyte alkaline phosphatase High uric acid	Bone marrow biopsy	Acute gouty arthritis Venous obstruction
Disease	Etiology	Demography	History	Constitutional symptoms	Weight	Bleeding	Abdominal Pain	Vital sign	Jaundice	LAP	Hepatosplenomegaly	Other	CBC	Histopathology	Other	Gold standard diagnosis	Associated findings
Chronic lymphocytic leukemia	Progressive accumulation of monoclonal B lymphocytes	The most common leukemia in adults in Western countries M > F Median age 70 years old	Positive family history Exposure to herbicides or insecticides	Generalized weakness Anorexia	↓	+	+	Fever	–	+ The most common abnormal finding	+	Skin lesions (leukemia cutis) Night sweats Muscle wasting	Anemia Thrombocytopenia Absolute lymphocytosis >5000 cells/μl Neutropenia	Presence of smudge cells Monoclonality of kappa and lambda producing B cells Express CD19, CD20, CD23, and CD5 on the cell surface	Positive direct antiglobulin (Coombs) test Hypogammaglobulinemia Elevated levels of serum lactate dehydrogenase and beta-2 microglobulin	Flow cytometry of the peripheral blood	Extranodal involvement of skin, kidney, lung, spine Membranoproliferative glomerulonephritis Autoimmune hemolytic anemia
Hairy cell leukemia	Accumulation of small mature B cell lymphoid cells with abundant cytoplasm and "hairy" projections BRAF mutation	Uncommon Median age 50 to 55 years old M >> F More in Caucasians than Blacks	Exposures to ionizing radiation, pesticides, and farming	Weakness and fatigue	↓	+	Abdominal fullness	Normal	–	±	+ Splenomegaly	Asymptomatic Spontaneous splenic rupture Skin rash Ascites Pleural effusion	Cytopenia Leukocytosis in 10 to 20 percent	Pancytopenia with monocytopenia and circulating tumor cells characteristic of HCL Dry bone marrow	Azotemia Abnormal liver function tests Hypergammaglobulinemia	Analysis of peripheral blood + immunophenotyping by flow cytometry	Vasculitis
Large granular lymphocytic leukemia​	Clonal proliferation of cytotoxic T cells Dysregulation of apoptosis through abnormalities in the Fas/Fas ligand pathway	Rare Median age 60 years M = F	Autoimmune diseases Lymphoproliferative disorders	Weakness and fatigue	↓	–	–	Fever	–	±	+	Mostly asymptomatic	Modest lymphocytosis Neutropenia Anemia Thrombocytopenia	Large lymphocytes with a condensed round or oval nucleus, abundant pale basophilic cytoplasm, and small azurophilic granules	Multiple serological abnormalities including rheumatoid factor, antinuclear antibody, antiplatelet antibodies, antineutrophil antibodies, positive direct Coombs test, hyper- or hypogammaglobulinemia, monoclonal gammopathies, and elevated β2-microglobulin	Biopsy and flow cytometry + T-cell receptor gene rearrangement studies	Recurrent bacterial infection
Chronic neutrophilic leukemia	Mature granulocytic proliferation in the blood and marrow Point mutations in the CSF3R gene	Very rare M = F	Multiple myeloma	Weakness and fatigue	↓	–	–	Fever	–	–	+ The most common clinical finding	Pruritus Gout	Peripheral blood neutrophilia (> 25 x 109/L) with myeloid precursors (promyelocytes, myelocytes, metamyelocytes)	Toxic granulation in the neutrophils Nuclear hypersegmentation Increased myeloid:erythroid ratio > 20:1	Elevated leukocyte alkaline phosphatase	WHO diagnostic criteria include leukocytosis of ≥ 25 x 109/L More than 80% neutrophils, Less than 10% circulating neutrophil precursors with blasts	Poor prognosis Absence of the Philadelphia chromosome or a BCR/ABL fusion gene
Disease	Etiology	Demography	History	Constitutional symptoms	Weight	Bleeding	Abdominal Pain	Vital sign	Jaundice	LAP	Hepatosplenomegaly	Other	CBC	Histopathology	Other	Gold standard diagnosis	Associated findings

Epidemiology and Demographics

Prevalence

• In the United States, the age-adjusted prevalence of leukemia is 75.3 per 100,000 in 2011.

Incidence

• The delay-adjusted incidence of leukemia in 2011 was estimated to be 15.48 per 100,000 persons in the United States.

• In 2011, the age-adjusted incidence of leukemia was 13.66 per 100,000 persons in the United States.

Age

• The overall age-adjusted incidence of leukemia in the United States between 2007 and 2011 is 13 per 100,000, the age-adjusted incidence of leukemia by age category is:
  • Under 65 years: 6.5 per 100,000
  • 65 and over: 57.9 per 100,000

• Shown below is a table depicting the overall age-adjusted incidence of leukemia per 100,000 individuals by age in the United States between 2007 and 2011 for the different types of leukemia.

	Acute lymphoblastic leukemia	Chronic lymphocytic leukemia	Acute myeloid leukemia	Chronic myeloid leukemia
All ages	1.7	4.4	3.8	1.7
<65	1.7	1.4	1.8	0.9
≥65	1.6	25.2	17.5	6.8

Gender

• In the United States, the age-adjusted prevalence of leukemia by gender in 2011 is:
  • In males: 92.7 per 100,000
  • In females: 60.7 per 100,000
• In the United States, the delay-adjusted incidence of leukemia by gender in 2011 is:
  • In males: 19.93 per 100,000 persons
  • In females: 11.89 per 100,000 persons

• In the United States, the age-adjusted incidence of leukemia by gender on 2011 is:
  • In males: 17.58 per 100,000 persons
  • In females: 10.49 per 100,000 persons

• Shown below is an image depicting the delay-adjusted incidence and observed incidence of leukemia by gender and race in the United States between 1975 and 2011. These graphs are adapted from SEER: The Surveillance, Epidemiology, and End Results Program of the National Cancer Institute.

Race

• Shown below is a table depicting the age-adjusted prevalence of leukemia by race in 2011 in the United States.

	All Races	White	Black	Asian/Pacific Islander	Hispanic
Age-adjusted prevalence	75.3 per 100,000	83.5 per 100,000	45.9 per 100,000	41.2 per 100,000	57.1 per 100,000

• Shown below is an image depicting the incidence of leukemia by race in the United States between 1975 and 2011.

API: Asian/Pacific Islander; AI/AN: American Indian/ Alaska Native

Prognosis

5-Year Survival

• Between 2004 and 2010, the 5-year relative survival of patients with leukemia was 60.3%.

• When stratified by age, the 5-year relative survival of patients with leukemia was 68.5% and 44.1% for patients <65 and ≥ 65 years of age respectively.

• Shown below is a table depicting the 5-year relative survival of patients by the type of leukemia in the United States between 2004 and 2010.

	Acute lymphoblastic leukemia	Chronic lymphocytic leukemia	Acute myeloid leukemia	Chronic myeloid leukemia
5-year survival	70%	83.5%	25.4%	59.9%