Staging acute lymphoblastic leukemia

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.

Acute lymphoblastic leukemia (ALL) has no standard staging system. The phases of ALL are described as untreated, in remission, relapsed (also called recurrent) or refractory.

Untreated ALL means that the leukemia is newly diagnosed and hasn’t been treated yet. Untreated ALL is defined by the following:

• there are low numbers of normal red blood cells, white blood cells and platelets
• usually more than 25% of the cells in the bone marrow are immature white blood cells (called blast cells, blasts or leukemia cells)
• there are signs and symptoms of ALL

Doctors use a complete blood count (CBC) to check the numbers of different types of blood cells.

After ALL 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 (red blood cells, white blood cells and platelets) are normal
• less than 5% of the cells in the bone marrow are leukemia cells
• there are no general signs or symptoms of ALL, 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 leukemia cells.

Relapsed, or recurrent, ALL 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 leukemia cells.

Refractory disease means the leukemia did not respond to treatment.