Doctors use staging to help them predict the progression of leukemia and develop an appropriate treatment plan. While most cancers are staged based on the size and spread of tumors, leukemia staging is a little bit different because it already occurs in the developing blood cells and/or in the bone marrow. Factors affecting leukemia staging and prognosis (the most likely outcome) include:

  • White blood cell or platelet count
  • Any history of blood disorders
  • Age 
  • Bone damage
  • Enlarged liver or spleen
  • The presence of inherited chromosome mutations, specifically the Philadelphia chromosome

Below are the various staging systems used for the four most common types of leukemia

Chronic Lymphocytic Leukemia (CLL) Stages

Unlike many other cancers that form tumors, CLL is generally in the bone marrow and blood. And, in many cases, has spread to other organs such as the spleen, liver, and lymph nodes by the time it’s found. If you have been diagnosed with CLL, your stage will depend on other information such as the results of lab and imaging tests.

When it comes to staging CLL, there are two primary systems that can be used: the Rai system and the Binet System. Both of these staging systems, which have been in use for many years, although the Rai System is more commonly used in the United States.

Rai Staging System

Low risk (Stage 0)
Abnormal increase in the number of lymphocytes in the blood and marrow
Intermediate risk (Stages I and II)
Abnormal increase in the number of lymphocytes in the circulating blood and the marrow
  • Enlarged lymph nodes
  • Abnormal increase in the number of lymphocytes in the circulating blood and the marrow
  • Enlarged spleen and/or liver
High Risk (Stages III & IV)
  • Abnormal increase in the number of lymphocytes in the circulating blood and the marrow
  • Anemia (hemoglobin <11g/dL)
  • Abnormal increase in the number of lymphocytes in the circulating blood and the marrow
  • Thrombocytopenia (platelet counts <100,000/uL)

Acute Myeloid Leukemia (AML) Stages

There are two main systems that have been used to classify AML into subtypes. They are the French-American-British (FAB) classification and the newer World Health Organization (WHO) classification.

French-American-British (FAB) Classification

The FAB classification was created in the 1970s by a group of French, American, and British leukemia experts who divided AML into subtypes, M0 through M7, based on the type of cell the leukemia develops from and how mature the cells are. This was based largely on how the leukemia cells looked under the microscope after routine staining.

Subtypes M0 through M5 all start in immature forms of white blood cells. M6 AML starts in very immature forms of red blood cells, while M7 AML starts in immature forms of cells that make platelets.

World Health Organization (WHO) Classification

Unlike the FAB classification system, the WHO classification system takes into account many of the factors that are now known to affect the prognosis (outlook) that can better classify AML. The WHO system divides AML into several groups.

French-American-British (FAB) Classification
  • M0: Undifferentiated acute myeloblastic leukemia
  • M1: Acute myeloblastic leukemia with minimal maturation
  • M2: Acute myeloblastic leukemia with maturation
  • M3: Acute promyelocytic leukemia (APL)
  • M4: Acute myelomonocytic leukemia
  • M4 eos: Acute myelomonocytic leukemia with eosinophilia
  • M5: Acute monocytic leukemia
  • M6: Acute erythroid leukemia
  • M7: Acute megakaryoblastic leukemia
World Health Organization (WHO) Classification
  • AML with certain genetic abnormalities (gene or chromosome changes)
  • AML with myelodysplasia-related changes
  • AML related to previous chemotherapy or radiation
  • AML not otherwise specified (this includes cases of AML that don’t fall into one of the above groups)
  • Myeloid sarcoma (also known as granulocytic sarcoma or chloroma)
  • Myeloid proliferations related to Down syndrome
  • Undifferentiated and biphenotypic acute leukemias (leukemias that have both lymphocytic and myeloid features), which are sometimes called mixed phenotype acute leukemias (MPALs)

Chronic Myeloid Leukemia (CML) Stages

CML is classified into 3 groups that help predict outlook. Rather than being called stages, doctors call these groups phases. The phases are based mainly on the number of immature white blood cells (blasts) in the blood or bone marrow.

There 3 phases of CML are: 

  • Chronic: This is the earliest phase of CML. The majority of CML patients usually have mild symptoms, particularly fatigue, and usually respond to standard treatments. 
  • Accelerated: If CML has not responded to treatment well during the chronic phase, it becomes more aggressive, which can lead to the accelerated phase. At this point, symptoms may become more noticeable and can include fever, poor appetite, and weight loss. 
  • Blastic: This is the most aggressive stage of chronic myeloid leukemia. Blastic refers to having more than 20% blasts. Symptoms in this phase are similar to those of acute myeloid leukemia.

Acute Lymphocytic (Lymphoblastic) Leukemia (ALL) Stages

Rather than using traditional staging methods, doctors have found that cytogenetic tests, flow cytometry, other lab tests, and factoring in the patient’s age provide more detailed information about the subtype of ALL and the prognosis. These tests help divide ALL into groups based on the gene and chromosome changes in the leukemia cells. 

The WHO system divides ALL into several groups, which include:

  • B-Cell ALL. B lymphocytes, or B cells, are a type of white blood cell that plays a large role in protecting your body from infection (humoral immunity) by making antibodies against antigens. 
  • T-Cell ALL. T cells play a central role in cell-mediated immunity. They are vital in hosting an immune response against pathogens.

What's Next After Leukemia Staging?

There are a lot of details that go into determining where you are in the development of a particular type leukemia. Thankfully, because of clinical research, we have many new treatments available to us and we're able to customize treatments based on many different factors, including any chromosomal mutations.

Learn more about leukemia treatments that are available today. Talk with your hematologic oncologist about what's right for you, or request a second opinion so you're confident in the treatment plan you're going to use.

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