Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.

There are three main types of cancer which affect various parts of the body, these are:

Carcinomas: Cancer that develops in the inner and outer surfaces of the body, such as the skin, the lining of the gastrointestinal tract, the inside of blood vessels, and the lungs. Like all cancers, carcinomas are malignant tumours in which cells grow uncontrollably, eventually crowding out normal cells. Also carcinomas often spread to other areas of the body or metastasize via the blood or lymphatic system. Different kinds of carcinomas include breast cancer, cervical cancer, prostate cancer, lung cancer, colon cancer, liver cancer, and skin cancer.

Sarcomas: Sarcomas are malignant (cancerous) tumours that develop in tissues which connect, support, or surround other structures and organs of the body. Muscles, tendons (bands of fiber that connect muscles to bones), fibrous tissues, fat, blood vessels, nerves, and synovial tissues are types of soft tissue that are affected.

Leukemias: Several types of cancers that affect blood cells, including oxygen-carrying red cells; certain infection-fighting white cells, such as granulocytes, macrophages and lymphocytes; and platelets, which aid in blood clotting.


Leukemias

My chosen cancer type is Leukemias. It is a very remarkable cancer as can it occurs in anyone and occurs in a system that cannot be seen.  Anyone can get leukemia.  Leukemia affects all ages and sexes. The cause of leukemia is not known. Chronic exposure to benzene in the workplace and exposure to extraordinary doses of irradiation can be causes of the disease, although neither explains most cases.

Leukemia is a form of cancer in which the body produces too many white blood cells. Many forms of leukemia have been identified. They are divided into two general types: acute and chronic. An acute condition comes on fairly quickly. A chronic disorder develops more slowly over time.

Causes

No one knows what causes leukemia. Researchers have strong suspicions about four possible causes, however. They are radiation, chemicals, viruses, and genetic factors.

·         Radiation. The term "radiation" refers to various forms of energy, such as X rays and ultraviolet (UV) light found in sunlight. Radiation can tear chemicals apart, thus damaging or destroying cells. Some researchers believe that exposure to radiation can cause some forms of leukemia.

·         Chemicals. Some types of chemicals are known to be carcinogens. A carcinogen is anything that can cause cancer. Chemicals can cause cancer by damaging cells and the substances within them.

·         Viruses. Some researchers believe that some types of leukemia are viral infections. A virus is a very small organism that can cause a disease. The link between viruses and leukemia is strong in some cases, but it has not been proved.

·         Genetics. Leukemia tends to occur in some families more commonly than in others. This suggests that at least some forms of leukemia may be hereditary.

Prevalence

Gender: Incidence rates for all types of leukemia are higher among males than among females. In 2008, females are expected to account for more than 56 percent of the cases of leukemia, although in 1997 this was the contrary.

Race: Leukemia rates are higher in people of European descent than among those of any other race/ethnicity. However, incidence rates for all types of cancer combined are more than 5 percent higher among people of African descent than among those of European descent. The incidence rate for all cancers among African Americans, from 2001-2005, was 500.6 per 100,000 population, averaging about 190,895 cases each year. From 1995 to 2004, incidence rates for leukemia have shown the greatest decline in American Indian/Alaska natives. Leukemia incidence is highest among whites and lowest among American Indians/Alaskan natives.                                                                                      

Age: Incidence rates by age differ for each of the Leukemias. The Leukemias represented 27 percent of all cancers occurring among children younger than 20 years of age from 2001-2005. It is estimated that in 2008, 4,532 children will be diagnosed with leukemia throughout the United States.

 

Statistics of leukemia by country

Country/Region 
Population 
Affected

South Africa 
44,448,470 
5,033

Russia 
143,974,059 
16,302

USA 
293,655,405 
33,252

India 
1,065,070,607 
120,603

Egypt 
76,117,421 
8,619

Australia 
19,913,144 
2,254

Angola 
10,978,552 
1,243

Signs and Symptoms

Some signs or symptoms of leukemia are similar to other more common and less severe illnesses. Specific blood tests and bone marrow tests are needed to make a diagnosis. Signs and symptoms vary based on the type of leukemia.

For acute leukemia, they include:

·         Tiredness or no energy

·         Shortness of breath during physical activity

·         Pale skin

·         Mild fever or night sweats

·         Slow healing of cuts and excess bleeding

·         Black-and-blue marks (bruises) for no clear reason

·         Pinhead-size red spots under the skin

·         Aches in bones or joints (for example, knees, hips or shoulders)

·         Low white cell counts, especially monocytes or neutrophils.


Treatment

·         Chemotherapy to kill leukemia cells using strong anti-cancer drugs.

·         Interferon therapy to slow the reproduction of leukemia cells and promote the immune system's anti-           leukemia activity.

·         Radiation therapy to kill cancer cells by exposure to high-energy radiation.

·         Stem cell transplantation (SCT) to enable treatment with high doses of chemotherapy and radiation therapy.

·         Surgery to remove an enlarged spleen or to install a venous access device (large plastic tube) to give  medications and withdraw blood samples.

Diagnosis

A complete blood count (CBC) is used to diagnose leukemia. This blood test may show high or low levels of white cells and show leukemic cells in the blood. Sometimes, platelet counts and red cell counts are low. Bone marrow tests (aspiration and biopsy) are often done to confirm the diagnosis and to look for chromosome abnormalities. These tests identify the leukemia cell-type. A complete blood exam and a number of other tests are used to diagnose the type of leukemia. These tests can be repeated after treatment begins to measure how well the treatment is working.

 

Survival Rate

The five-year relative survival rate has nearly quadrupled in the past 48 years for patients with leukemia. In 1960-63, when compared to a person without leukemia, a patient had a 14 percent chance of living five years.  By 1975-1977, the five year relative survival rate had jumped to 35 percent, and in 1996-2004 the overall relative survival rate was slightly above 50 percent (51.2 percent). The relative survival rates differ by the age of the patient at diagnosis, gender, race and type of leukemia.

During 1996- 2004 relative survival rates overall were:

·         Acute lymphocytic leukemia (ALL): 66.1 percent overall; 91.2 percent for children under 5.

·         Chronic lymphocytic leukemia (CLL): 76.2 percent.

·         Acute myelogenous leukemia (AML): 21.3 percent overall; 55.2 percent for children under 15.

·         Chronic myelogenous leukemia (CML): 46.7 percent.

 

Conclusion

Leukemia is a cancer of blood-forming cells in the bone marrow. These cells crowd out other types of blood cells produced by the bone marrow, including red blood cells, which carry oxygen to tissues throughout your body, and platelets, which help form blood clots. Leukemia cells can spread to the lymph nodes or other organs causing swelling and/or pain and can also collect in the kidney, liver and spleen, causing enlargement of these organs. Acute forms can occur in children and young adults. Chronic forms mostly occur in older people, but can also occur in any age group. Leukemia has been dramatically increasing, especially among children, but also various other age groups. No causes have been found to have identified the increase of leukemia although our change in lifestyle might play a role.

There is no single known cause for all of the different types of leukemia. Studies have linked exposure to petrochemicals, such as benzene, and hair dyes to the development of some forms. Viruses have been linked to other forms. Until the cause or causes are found, there is no known way to prevent the occurrence of the disease.

References/Bibliography

·         http://www.cansa.org.za/cgibin/giga.cgi?cmd=cause_dir_news_item&cause_id=1056&news_id=31937&cat_id=820

·         http://www.cansa.org.za/cgibin/giga.cgi?cmd=cause_dir_news_item&cause_id=1056&news_id=35591&cat_id=1022

·         http://www.leukemia-lymphoma.org/all_page.adp?item_id=9346

·         http://www.wrongdiagnosis.com/l/leukemia/stats-country.htm

·         http://encarta.msn.com/encyclopedia_761573290/leukemia.html