Acute
A sudden onset of symptoms or disease.

Acute lymphocytic leukemia (ALL)
In 80 per cent of childhood leukemia, the lymphocyte production goes haywire, leading to the form of leukemia called acute lymphocytic or lymphoblastic leukaemia (ALL). The lymphoblasts (or blasts) stay immature and reproduce when they should not, crowding the bone marrow so normal cells do not have enough room to multiply and mature.

Eighty percent of all ALL is seen in children, with more boys than girls affected. The incidence of ALL peaks in late infancy, preschool years and around puberty. Forty per cent of ALL cases appear in children ages three to five.

Acute non-lymphocytic leukemia (ANLL)
ANLL accounts for nearly 20 per cent of leukemia in children. Unlike ALL, there is no age at which ANLL peaks in children. Its incidence increases with age, from childhood through adolescence and young adulthood to middle age. The incidence of ANLL drops off after the age of 65.

Acute lymphoblastic leukemia (ALL)
A form of leukemia characterized by the replacement of normal bone marrow by immature (blast [link]) cells of the blood-forming series. Eighty per cent of cases are in children less than 10 years of age. Cure rate is over 80 per cent.

Acute myeloblastic leukemia (AML or ANLL — Acute non-lymphocytic leukemia)
AML and ANLL account for 20 per cent of childhood leukemia with incidence increasing with age. Cure rate is 40 per cent.

Adjuvant therapy
Therapy that supports or enhances an additional form of therapy in the treatment of disease, i.e., surgical therapy in addition to chemotherapy.

Adrenal gland
A small gland lying on top of each kidney, which secretes hormones such as steroids, androgens and hormones that affect blood pressure as well as epinehprine.

Alopecia
The loss of body hair often as the result of chemotherapy or radiotherapy.

Anaesthetic
Anaesthetic is a drug administered by a specialist called an anaestheologist before surgery or other painful medical procedures to block the feeling of pain and other sensations. Anaesthesia is considered a reversible lack of awareness. There are general and local anaesthetics. General anaesthetic induces a complete lack of awareness or consciousness in the patient, whereas a local anaesthetic induces a lack of awareness of a particular body part, while the patient remains otherwise conscious.

Analgesia
A drug that relieves pain.

Anaemia
A decreased number of red blood cells, causing fatigue, weakness and shortness of breath.

Anorexia
Loss of appetite.

Antibodies
Antibodies are secreted by the immune system to help fight infection. Also known as immunoglobulins, antibodies are proteins found in blood or other bodily fluids of vertebrates that are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses.

Anti-emetic
A drug that prevents or controls nausea and vomiting such as Gravol or ondansetron.

Antigen
A foreign substance that stimulates the body’s production of antibodies.