These are commonly called “blood cancer”. In fact, these are cancer of the bone marrow which produces the cells, viz. red and white blood cells and the platelets that circulate in the blood. In this condition, the white blood cells produced in the bone marrow arc cancerous and immature. They are also produced in number much more than the normal cells. That is why the condition is called Leukemia, literally meaning white blood. The other cells produced in the marrow such as the red blood cells and the platelets are produced less.
Untreated, the Leukemias are progressive and fatal; death occurs from anaemia, bleeding (haemorrhage) or repeated infections. The course may vary from a few weeks to several years depending upon the severity of the condition and the type of white blood cells involved. Some Leukemias run an acute course, others a chronic one. The leukaemic process effects cither the precursors of the lymphocytes, or the granulocytes also called myeloid cells.
Of all the varieties of Leukemia, acute lymphoblastic Leukemia (ALL) involving the precursors of lymphocyte, i.e. the lymphoblasts, is the commonest in children; it forms one-third of all childhood cancers. It occurs between the age of 2 to 7 years, and is uncommon after the age of 15 years.
In adults, the common acute Leukemia is non-lymphocytic (ANLL), also called acute myelogenous Leukemia (AML) because it involves myeloid cells.
Acute lymphoblastic Leukemia, the type commonly found in children, is rare in adults.
Leukemias arc thus classified as:
· Acute lymphoblastic and acute non-lymphoblastic (also called acute myeloid).
· Chronic lymphocytic and non-lymphocytic.