Acute Leukaemia Download PDF, 1.01MB, PDF Leukaemia is a form of cancer that arises in the bone marrow, causing an uncontrolled production of abnormal white blood cells. There are two forms of leukaemia, acute and chronic.Acute leukaemia comes on suddenly, often within days or weeks. It progresses quickly and needs to be treated urgently. Chronic leukaemia develops more slowly, often over many months or years. [Please download the PDF file if you are unable to view the image below.]