Leukemia is the term for the four major types of leukemia.
1. Acute lymphocytic leukemia (ALL) 2. Chronic lymphocytic leukemia (CLL)
3. Acute myelogenous leukemia (AML) 4. Chronic myelogenous leukemia (CML)
The terms “myelogenous (myeloid)” and “lymphocytic (lymphoblastic)” denote the cell types involved. In general, leukemia is characterized by the uncontrolled accumulation of blood cells. However, the natural history of each type, and the therapies used to treat people with each type, are different.
Living with Leukemia
An estimated 245,225 people in the United States are living with, or are in remission from, leukemia.
ALL and AML are diseases that progress rapidly without treatment. They result in the accumulation of immature, functionless cells in the marrow and blood. The marrow often stops producing enough normal platelets, red cells and white cells. Anemia, a deficiency of red cells, develops in virtually all people who have leukemia. The lack of normal white cells impairs the body’s ability to fight infections. A shortage of platelets results in bruising and easy bleeding.
CLL and CML usually progress slowly compared to acute types of leukemia. The slower disease progression allows greater numbers of more mature, functional cells to be made.
An estimated 44,790 new cases of leukemia will be diagnosed in the United States this year. Cases of chronic leukemia account for nearly 11 percent more cases than acute leukemia.
• Most cases of leukemia occur in older adults and the median age at diagnosis is 66 years.
• In 2009, leukemia is expected to strike more than 10 times as many adults (44,790) as children (3,509, aged 0-14 years).
• The most common types of leukemia in adults are AML and CLL.
• The most common type of leukemia in children is ALL.
• In 2006, the latest year for which data are available, 70 percent of new cases of ALL occurred among children (2,887 cases, aged 0 to 19 years).
• Most cases of CML occur in adults. Only about 2.4 percent of new cases of leukemia in children aged 0 to 19 years are CML. Slightly less than 1 percent of all cases of CML are in children aged 15 to 19 years.
Gender. Incidence rates for all types of leukemia are higher among males than among females. In 2009, males are expected to account for more than 57 percent of the new cases of leukemia.
Race and Ethnicity. Leukemia is one of the top 15 most frequently occurring types of cancer in all races or ethnicities.
• Leukemia incidence is highest among whites (12.8 per 100,000 population) and lowest among American Indian and Alaska Native populations (7.0 per 100,000), Asian and Pacific Islander populations (7.3 per 100,000).
• While incidence rates for all types of cancer combined are nearly 5 percent higher among blacks* than among whites, leukemia rates are higher among whites than among other races or ethnicities.
• From 1997 to 2006, incidence rates for leukemia have shown the greatest decline in white, Asian and Pacific Islander populations.
• Leukemia rates are substantially higher for children who are Hispanic, white, Asian, Pacific Islander, American Indian and Alaska Native than for black children.
• Hispanic children of all races under the age of 20 years have the highest rates of leukemia.
Note: The incidence rate for all types of cancer among blacks in the SEER 17 region, from 2002 to 2006, was 493.6 per 100,000 population, averaging about 190,356 cases per year. The American Cancer Society estimates that about 150,090 of the expected 1.5 million new cancer cases in 2009 will be diagnosed in blacks.
Children. From 2002 to 2006, leukemia represented 27 percent of all of the types of cancer occurring among children younger than 20 years.
• Leukemia is the most common cancer in children less than 20 years old.
• In 2009, about 3,509 children less than 15 years old will be diagnosed with leukemia throughout the United States. About 33 percent of cancer cases in children aged 0 to 14 years are leukemia.
• In the 17 SEER regions of the United States, excluding Louisiana, from 2004 to 2006, there were 2,901 children under the age of 20 years diagnosed with leukemia, including 1,203 diagnosed with ALL.
• ALL is the most common cancer in children 1 to 7 years old.
• The incidence of ALL among 1- to 4-year olds is nearly eight times greater than the rate for young adults 20 to 24 years. Adolescents and Young Adults. AML incidence is much higher in children from 0 to 14 years than it is in people aged 15 years through young adulthood.
• In 2002 to 2006, among 15- to 19-year olds, ALL incidence was almost twice that of AML.
• In 25- to 29-year olds, AML incidence was 29 percent higher than that of ALL
• From 1975 to 2006, the incidence of AML declined slightly for all age-groups. Adults. CLL, AML and CML are most prevalent in the seventh, eighth and ninth decades of life. Incidence begins to increase significantly among people with
• CLL—at aged 50 years and older
• AML—at aged 55 years and older
CML—at aged 55 years and older.
Signs and Symptoms
Signs of acute leukemia may include easy bruising or bleeding (because of platelet deficiency), paleness or easy fatigue (because of anemia), recurrent minor infections or poor healing of minor cuts (because of an inadequate white cell count). These signs are not unique to leukemia and may be caused by other more common conditions. Nonetheless, they do warrant medical evaluation. The diagnosis of leukemia requires specific blood tests, including an examination of cells in the blood and marrow. People who have chronic leukemia may not have major symptoms; they may be diagnosed as a result of a periodic physical examination and testing.
Leukemia strikes males and females of all ages. The cause of leukemia is not known. Chronic exposure to benzene (primarily from tobacco smoke), extraordinary doses of radiation, and certain cancer therapies, can be causes of the disease. However, most cases are not explained by any of these causes.
The goal of treatment for leukemia is to bring about a complete remission. Complete remission means that there is no evidence of disease and the individual returns to good health with normal blood and marrow cells. Relapsed leukemia indicates return of the cancer cells and the return of disease signs and symptoms. For acute leukemia, a complete remission that lasts five years after diagnosis often indicates long-term survival. Treatment centers report increasing numbers of people with leukemia who are in complete remission at least five years after diagnosis of their disease.
Relative survival rates vary according to a person’s age at diagnosis, gender, race and type of leukemia. The overall five-year relative survival rate for leukemia has nearly quadrupled in the past 48 years. From 1960 to1963, the five-year relative survival rate among whites with leukemia was 14 percent. From 1975 to 1977, the five- year relative survival rate for the total population with leukemia was 35 percent and from 1999 to 2005, the overall relative survival rate was 54 percent. Thirty-one percent more males than females are living with leukemia.
From 1999 to 2005, the five-year relative survival rates overall were:
• CML—53.3 percent
• CLL—78.8 percent
• AML—23.4 percent overall and 60.2 percent for children younger than 15 years
• ALL—66.3 percent overall and 90.9 percent for children younger than 5 years.
In 2009, it is anticipated that approximately 21,870 deaths (12,590, males and 9,280, females) in the United States will be attributed to leukemia.
Estimated deaths for the four major types of leukemia are:
• AML—9,000 deaths estimated, 2009
• CLL—4,390 deaths estimated, 2009
• ALL—1,400 deaths estimated, 2009
• CML—470 deaths estimated, 2009.
For other, unclassified forms of leukemia an additional 6,610 deaths are estimated for 2009. In general, the likelihood of dying from most types of leukemia decreased from 1996 to 2005 (the latest year for which these data are available). However, the likelihood of dying from AML increased from 1996 to 2005.
Gender. In 2009, leukemia will be the fifth most common cause of cancer deaths in men and the seventh most common in women in the United States. The estimated number of deaths attributed to leukemia in the United States is nearly 36 percent higher for males than for females.
Race and Ethnicity. The highest rate of deaths from 2002 to 2006 was in whites, at 7.5 per 100,000 population, followed by blacks at 6.4 per 100,000.
• From 2002 to 2006, blacks diagnosed with leukemia between the ages of 25 and 64 years had a higher death rate than whites from the disease.
• In 2009, approximately 1,830 blacks (970 males and 860 females) are expected to die of leukemia.
• Leukemia is the seventh most common cause of cancer deaths in black males and the eighth most common in black females. Children, Adolescents and Young Adults. The leukemia death rate for children from 0 to 14 years in the United States has declined 88 percent from 1969 to 2006.
• Despite this decline, leukemia causes more deaths than any other cancer among children and young adults less than age 20 years.
• In 2009, about 460 children under 15 years are expected to die from leukemia.
This information has been provided by the Leukemia and Lymphoma Society.