Acute childhood leukemias can be divided into four major categories as follows.
- ALL = acute lymphoblastic leukemia (75%)
- AML= acute myelogenous leukemia (20%)
- NHL = non-Hodgkin’s lymphomas (4-5%)
- Burkitt’s lymphoma (part of NHL) (small fraction of NHL)
There are three more common acute childhood leukemias, acute lymphoblastic leukemia (ALL), acute myelogenous leukemia(AML) and non-Hodgkin’s lymphoma (NHL). I apologize for the complex doctor terminology and the abbreviations. However, these terms are what anyone, who gets involved with the treatment of such a condition, will hear a lot in doctor’s offices and hospitals.
Causes of leukemia
Acute leukemia is the most common malignancy in children. It occurs in the bone marrow and may be common in childhood because the bones are experiencing a lot of changes with normal growth. 75% of the 2000 cases of childhood leukemia are ALL, 20% are AML and about 5% are NHL. The peak in incidence for ALL is between 2 and 6 years of age. It occurs more often in boys than in girls and is not observed in blacks. AML occurs more often in girls between the ages of 5 and 15 years. Beyond the age of 15 years boys are affected more commonly with AML.
Radiation effects of the atom bomb
Following the atom bomb explosions in Hiroshima and Nagasaki in 1945 people closest to the center of the explosion developed leukemia. Among children it was mostly ALL that they developed. The cell-toxic medications that are used to combat the ALL in childhood often caused Hodgkin’s disease when these children became adults.
The early days of neon lights
In the early days of neon lights there were reports of leukemia from unsafe neon light bulbs in school classes. It turned out that there had been a manufacturing problem where light bulbs were emitting X rays and the chronic exposure to X rays led to leukemia. This has not been a problem for decades, because manufacturers have strict controls to ensure this cannot happen again. But the myth (from a fact in the past) lives on.
There is an increased risk for children to develop leukemia when the fetus is exposed to diagnostic X rays when a woman is in a first trimester pregnancy.
Benzene, a chemical that is used in industry with production of detergents, plastic manufacturing, insecticides and others, is a known cause of leukemia, mainly AML.
There is a hint that there likely is a genetic cause concerning the development of leukemia as Down syndrome (trisomy 21) has a 15-fold risk to develop leukemia than normal children do. There are other rare genetic abnormalities of which some are associated with a higher risk of leukemia. Finally, there is a link to certain viral infections such as Epstein-Barr virus, which can cause Burkitts lymphoma (if the population is starved as in Africa). On the other hand HTLV is a virus where two subtypes, HTLV-I and HTLV-II, have been characterized in the meantime and that have been associated with certain human leukemias.
Power lines and leukemia
There have been lengthy discussions about whether living near power lines could cause leukemia. Research in 2005 showed that there is a weak effect when you live very close to power lines, but the effect has been exaggerated by many.