Staging acute myelogenous leukemia (AML)
Staging is a way of describing or classifying a cancer based on the extent, or amount, of cancer in the body. Cancers that form solid tumours are given numbered stages based on the size of the tumour and if the cancer has spread to lymph nodes or other parts of the body.
There is no standard staging system for acute myelogenous leukemia (AML). It is described as untreated, in remission, relapsed (also called recurrent) or refractory.
Untreated AML means that the leukemia is newly diagnosed. It hasn’t been treated yet, other than to relieve symptoms. Untreated AML is defined by:
- immature blood cells (called blast cells, or blasts) may be seen in the blood sample
- at least 20% of the cells in the bone marrow are blast cells
- there are usually signs and symptoms of AML
Doctors use a complete blood count (CBC) to check the numbers of different types of blood cells.
After AML is treated, the leukemia can be in remission.
Complete remission, or complete response, means that all of these criteria apply:
- the numbers of blood cells (neutrophils and platelets) have recovered to an absolute neutrophil count greater than 1 x 109/L and a platelet count greater than 100 x 109/L, without blood transfusion
- less than 5% of the cells in the bone marrow are blast cells
- there are no general signs or symptoms of AML, such as fatigue, weight loss, fever, anemia or bleeding
- there are no signs or symptoms of leukemia in the brain and spinal cord (called the central nervous system, or CNS) or anywhere else in the body
Partial remission means that less than 25% of the cells in the bone marrow are blast cells.
Relapsed, or recurrent, AML means the leukemia has come back after treatment and reaching remission. Relapse means that more than 25% of the cells in the bone marrow are blast cells.
Refractory disease means the leukemia did not respond to treatment.
National Cancer Institute. Adult Acute Myeloid Leukemia Treatment (PDQ®) Health Professional Version. Bethesda, MD: National Cancer Institute; 2014: http://www.cancer.gov.
Tuzner NN, Bennett JM . Classification of the acute leukemias: cytochemical and morphologic considerations. Wiernik PH, Goldman JM, Dutcher JP & Kyle RA (eds.). Neoplastic Diseases of the Blood. 5th ed. Springer; 2013: 16: pp. 213-239.