Ingles Leucemia

Materia: English

Teacher: Carla

Carrera: Medicina

Fecha: 18-06-2013

Students: Capdevilla Badía y Aguzzi Lucia

Hypothesis: There is a greater likelihood of childhood leukemia in underdeveloped countries.

What is childhood leukemia?

About Leukemia

The term leukemia refers to cancers of the white blood cells (also called leukocytes or WBCs). When a child has leukemia, large numbers of abnormal white blood cells are produced in the bone marrow. These abnormal white cells crowd the bone marrow and flood the bloodstream, but they cannot perform their proper role of protecting the body against disease because they are defective.

As leukemia progresses, the cancer interferes with the body's production of other types of blood cells, including red blood cells and platelets. This results in anemia (low numbers of red cells) and bleeding problems, in addition to the increased risk of infection caused by white cell abnormalities.

As a group, leukemias account for about 25% of all childhood cancers and affect about 2,200 American young people each year. Luckily, the chances for a cure are very good with leukemia. With treatment, most children with leukemia will be free of the disease without it coming back.

Types of Leucemia

In general, leukemias are classified into acute (rapidly developing) and chronic (slowly developing) forms. In children, about 98% of leukemias are acute.

Acute childhood leukemias are also divided into acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML), depending on whether specific white blood cells called lymphyocytes (or myelocytes), which are linked to immune defenses, are involved. Approximately 60% of children with leukemia have ALL, and about 38% have AML. Although slow-growing chronic myelogenous leukemia (CML) may also be seen in children, it is very rare, accounting for fewer than 50 cases of childhood leukemia each year

General Statistics

The ALL form of the disease most commonly occurs in younger children ages 2 to 8, with a peak incidence at age 4. But it can affect all age groups.

Leukemia is the most common cancer in children and teens, accounting for almost 1 out of 3 cancers. Overall, however, childhood leukemia is a rare disease.

About 3 out of 4 leukemias among children and teens are acute lymphocytic leukemia (ALL). Most of the remaining cases are acute myelogenous leukemia (AML). Chronic leukemias are rare in children.

ALL is most common in early childhood, peaking between 2 and 4 years of age. Cases of AML are more spread out across the childhood years, but it is slightly more common during the first 2 years of life and during the teenage years.

ALL is slightly more common among white children than among African-American and Asian-American children, and it is more common in boys than in girls. AML occurs about equally among boys and girls of all races.

Due to advances in treatment, there has been a dramatic improvement in survival for people with acute lymphocytic leukemia, from a 5-year relative survival rate of 41% in 1975 to 1977 to 67% in 2001 to 2007 in adults. Survival rates for children with acute lymphocytic leukemia have increased from 58% to 91% over the same time period.

Since the early 1970s, incidence rates for non-Hodgkin’s lymphoma have nearly doubled.

The 1-year relative survival rates for Hodgkin's lymphoma and non-Hodgkin's lymphoma are 92% and 81% respectively; the 5-year rates are markedly lower at 84% and 67%; 10-year survival is 81% and 56% respectively.

The number of new cases seems to be going up, perhaps because our population is getting older and there are more cancer survivors who have had chemotherapy, an important risk factor for MDS.

• Every day 129 are diagnosed with leukemia and 60 lose the fight

• Every day 216 Americans are diagnosed with lymphoma and 55 lose the fight.

The age peak of cancer during infancy, especially those for leukemias and lymphomas, varies among countries.

Although the peak age for leukemias worldwide is principally

between 2–5 years of age, a peak as late as 7–13 years of age was reported for Níger.

In developed countries such as Germany or the United States of America

(USA), the age peak for lymphomas is between 10–14 years of age, whereas in less

developed countries, Mexico for example, the age peak is between 5–9 years of age.

Leukemia is the most common cancer in children under 15 years old, representing between 25–35% of all childhood cancers in most populations.

The main subtypes of leukemia described by most cancer registries include acute

lymphoblastic leukemia (ALL), representing about 80% of all leukemias; AML, with a

frequency of 15%; and chronic myeloid leukemia (CML) with a frequency of 3–5%

ALL is the most frequent leukemia in infancy.

What are the risk factors for childhood leukemia?

A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, smoking is a risk factor for several types of cancer in adults.

Lifestyle-related risk factors such as diet, body weight, physical activity, and tobacco use play a major role in many adult cancers. But these factors usually take many years to influence cancer risk, and they are not thought to play much of a role in childhood cancers, including leukemias. There are a few known risk factors for childhood leukemia.

Genetic risk factors

Genetic risk factors are those that are part of our. While some genetic factors increase the risk of childhood leukemia, most cases of leukemia are not linked to any known genetic causes.

Inherited syndromes

There are several inherited disorders that increase a child's risk of developing leukemia:

• Li-Fraumeni syndrome:

• Down syndrome (trisomy 21):

• Klinefelter syndrome

Having a brother or sister with leukemia

Siblings (brothers and sisters) of children with leukemia have a slightly increased chance (2 to 4 times normal) of developing leukemia, but the overall risk is still low. The risk is much higher among identical twins.

Lifestyle-related risk factors

Lifestyle-related risk factors for some adult cancers include being overweight, smoking, drinking excessive amounts of alcohol, and getting too much sun exposure. While lifestyle-related factors are important in many adult cancers, they are unlikely

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