ALL is a cancer of the white blood cells. Normally, white blood cells grow and divide in an orderly and controlled way.
In leukaemia this process gets out of control as the normal signals that stop the body making too many cells are ignored. So the cells go on dividing and do not mature.
In ALL there is an overproduction of immature lymphocytes, called lymphoblasts (sometimes referred to as blast cells).
These immature cells fill up the bone marrow and stop it from making new blood cells properly. As the lymphoblasts do not mature, they can't do the work of normal white blood cells (fight infection). And because the bone marrow is overcrowded with immature white cells, it can't make enough healthy red cells and platelets.
ALL occurs most frequently in children under 15; in adults it is most common between the ages of 15-25 and in people over 75. It's slightly more common in males than in females.
ALL and lymphoma
ALL is very similar to lymphoblastic lymphoma, which is a cancer of the lymphatic system. In ALL, the abnormal lymphocytes are generally in the blood and bone marrow, but in lymphoblastic lymphoma they are mainly in the lymph nodes or thymus gland. The two conditions are often treated in very similar ways.
Symptoms of acute lymphoblastic leukaemia
The main symptoms of ALL are caused by having too many blast cells in the bone marrow and too few normal blood cells in your blood.
- Looking very pale, feeling very tired or becoming breathless easily, caused by a lack of red blood cells (anaemia).
- Feeling generally unwell and run-down, perhaps with a sore throat or mouth.
- Aching joints and bones.
- Having various infections one after the other, caused by a lack of healthy white blood cells.
- Unusual bleeding, because of too few platelets. This may include bruising without any obvious cause, heavy periods in women, bleeding gums and frequent nosebleeds.
*Information provided by Macmillan cancer support